X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/43866e378188c25dd1e2208016ab3cbeb086ae6c..94ff46dc2849db4d43eaaf144872decc522aafb4:/bsd/kern/kern_event.c diff --git a/bsd/kern/kern_event.c b/bsd/kern/kern_event.c index f298f525b..8f4d2207b 100644 --- a/bsd/kern/kern_event.c +++ b/bsd/kern/kern_event.c @@ -1,17 +1,20 @@ /* - * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. + * Copyright (c) 2000-2019 Apple Inc. All rights reserved. + * + * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * - * @APPLE_LICENSE_HEADER_START@ - * - * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved. - * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in - * compliance with the License. Please obtain a copy of the License at - * http://www.opensource.apple.com/apsl/ and read it before using this - * file. - * + * compliance with the License. The rights granted to you under the License + * may not be used to create, or enable the creation or redistribution of, + * unlawful or unlicensed copies of an Apple operating system, or to + * circumvent, violate, or enable the circumvention or violation of, any + * terms of an Apple operating system software license agreement. + * + * Please obtain a copy of the License at + * http://www.opensource.apple.com/apsl/ and read it before using this file. + * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, @@ -19,212 +22,9172 @@ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. - * - * @APPLE_LICENSE_HEADER_END@ + * + * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ * */ +/*- + * Copyright (c) 1999,2000,2001 Jonathan Lemon + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ /* * @(#)kern_event.c 1.0 (3/31/2000) */ +#include +#include #include -#include -#include -#include -#include -#include +#include +#include +#include +#include +#include #include -#include -#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include // SYS_* constants +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include -int raw_usrreq(); -struct pr_usrreqs event_usrreqs; +#include +#include +#include +#include -struct protosw eventsw[] = { - { - SOCK_RAW, &systemdomain, SYSPROTO_EVENT, PR_ATOMIC, - 0, 0, 0, 0, - 0, - 0, 0, 0, 0, - 0, &event_usrreqs - } +#include "net/net_str_id.h" + +#include +#include + +#if CONFIG_MEMORYSTATUS +#include +#endif + +extern mach_port_name_t ipc_entry_name_mask(mach_port_name_t name); /* osfmk/ipc/ipc_entry.h */ + +#define KEV_EVTID(code) BSDDBG_CODE(DBG_BSD_KEVENT, (code)) + +MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); + +#define KQ_EVENT NO_EVENT64 + +static int kqueue_select(struct fileproc *fp, int which, void *wq_link_id, + vfs_context_t ctx); +static int kqueue_close(struct fileglob *fg, vfs_context_t ctx); +static int kqueue_kqfilter(struct fileproc *fp, struct knote *kn, + struct kevent_qos_s *kev); +static int kqueue_drain(struct fileproc *fp, vfs_context_t ctx); + +static const struct fileops kqueueops = { + .fo_type = DTYPE_KQUEUE, + .fo_read = fo_no_read, + .fo_write = fo_no_write, + .fo_ioctl = fo_no_ioctl, + .fo_select = kqueue_select, + .fo_close = kqueue_close, + .fo_drain = kqueue_drain, + .fo_kqfilter = kqueue_kqfilter, }; -static -struct kern_event_head kern_event_head; +static inline int kevent_modern_copyout(struct kevent_qos_s *, user_addr_t *); +static int kevent_register_wait_prepare(struct knote *kn, struct kevent_qos_s *kev, int result); +static void kevent_register_wait_block(struct turnstile *ts, thread_t handoff_thread, + thread_continue_t cont, struct _kevent_register *cont_args) __dead2; +static void kevent_register_wait_return(struct _kevent_register *cont_args) __dead2; +static void kevent_register_wait_cleanup(struct knote *kn); + +static struct kqtailq *kqueue_get_suppressed_queue(kqueue_t kq, struct knote *kn); +static void kqueue_threadreq_initiate(struct kqueue *kq, workq_threadreq_t, kq_index_t qos, int flags); + +static void kqworkq_unbind(proc_t p, workq_threadreq_t); +static thread_qos_t kqworkq_unbind_locked(struct kqworkq *kqwq, workq_threadreq_t, thread_t thread); +static workq_threadreq_t kqworkq_get_request(struct kqworkq *kqwq, kq_index_t qos_index); + +static void kqworkloop_unbind(struct kqworkloop *kwql); + +enum kqwl_unbind_locked_mode { + KQWL_OVERRIDE_DROP_IMMEDIATELY, + KQWL_OVERRIDE_DROP_DELAYED, +}; +static void kqworkloop_unbind_locked(struct kqworkloop *kwql, thread_t thread, + enum kqwl_unbind_locked_mode how); +static void kqworkloop_unbind_delayed_override_drop(thread_t thread); +static kq_index_t kqworkloop_override(struct kqworkloop *kqwl); +static void kqworkloop_set_overcommit(struct kqworkloop *kqwl); +enum { + KQWL_UTQ_NONE, + /* + * The wakeup qos is the qos of QUEUED knotes. + * + * This QoS is accounted for with the events override in the + * kqr_override_index field. It is raised each time a new knote is queued at + * a given QoS. The kqwl_wakeup_indexes field is a superset of the non empty + * knote buckets and is recomputed after each event delivery. + */ + KQWL_UTQ_UPDATE_WAKEUP_QOS, + KQWL_UTQ_UPDATE_STAYACTIVE_QOS, + KQWL_UTQ_RECOMPUTE_WAKEUP_QOS, + KQWL_UTQ_UNBINDING, /* attempt to rebind */ + KQWL_UTQ_PARKING, + /* + * The wakeup override is for suppressed knotes that have fired again at + * a higher QoS than the one for which they are suppressed already. + * This override is cleared when the knote suppressed list becomes empty. + */ + KQWL_UTQ_UPDATE_WAKEUP_OVERRIDE, + KQWL_UTQ_RESET_WAKEUP_OVERRIDE, + /* + * The QoS is the maximum QoS of an event enqueued on this workloop in + * userland. It is copied from the only EVFILT_WORKLOOP knote with + * a NOTE_WL_THREAD_REQUEST bit set allowed on this workloop. If there is no + * such knote, this QoS is 0. + */ + KQWL_UTQ_SET_QOS_INDEX, + KQWL_UTQ_REDRIVE_EVENTS, +}; +static void kqworkloop_update_threads_qos(struct kqworkloop *kqwl, int op, kq_index_t qos); +static int kqworkloop_end_processing(struct kqworkloop *kqwl, int flags, int kevent_flags); -static u_long static_event_id = 0; +static struct knote *knote_alloc(void); +static void knote_free(struct knote *kn); +static int kq_add_knote(struct kqueue *kq, struct knote *kn, + struct knote_lock_ctx *knlc, struct proc *p); +static struct knote *kq_find_knote_and_kq_lock(struct kqueue *kq, + struct kevent_qos_s *kev, bool is_fd, struct proc *p); + +static void knote_activate(kqueue_t kqu, struct knote *kn, int result); +static void knote_dequeue(kqueue_t kqu, struct knote *kn); + +static void knote_apply_touch(kqueue_t kqu, struct knote *kn, + struct kevent_qos_s *kev, int result); +static void knote_suppress(kqueue_t kqu, struct knote *kn); +static void knote_unsuppress(kqueue_t kqu, struct knote *kn); +static void knote_drop(kqueue_t kqu, struct knote *kn, struct knote_lock_ctx *knlc); + +// both these functions may dequeue the knote and it is up to the caller +// to enqueue the knote back +static void knote_adjust_qos(struct kqueue *kq, struct knote *kn, int result); +static void knote_reset_priority(kqueue_t kqu, struct knote *kn, pthread_priority_t pp); + +static zone_t knote_zone; +static zone_t kqfile_zone; +static zone_t kqworkq_zone; +static zone_t kqworkloop_zone; +#if DEVELOPMENT || DEBUG +#define KEVENT_PANIC_ON_WORKLOOP_OWNERSHIP_LEAK (1U << 0) +#define KEVENT_PANIC_ON_NON_ENQUEUED_PROCESS (1U << 1) +#define KEVENT_PANIC_BOOT_ARG_INITIALIZED (1U << 31) + +#define KEVENT_PANIC_DEFAULT_VALUE (0) +static uint32_t +kevent_debug_flags(void) +{ + static uint32_t flags = KEVENT_PANIC_DEFAULT_VALUE; + + if ((flags & KEVENT_PANIC_BOOT_ARG_INITIALIZED) == 0) { + uint32_t value = 0; + if (!PE_parse_boot_argn("kevent_debug", &value, sizeof(value))) { + value = KEVENT_PANIC_DEFAULT_VALUE; + } + value |= KEVENT_PANIC_BOOT_ARG_INITIALIZED; + os_atomic_store(&flags, value, relaxed); + } + return flags; +} +#endif + +#define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) + +static int filt_no_attach(struct knote *kn, struct kevent_qos_s *kev); +static void filt_no_detach(struct knote *kn); +static int filt_bad_event(struct knote *kn, long hint); +static int filt_bad_touch(struct knote *kn, struct kevent_qos_s *kev); +static int filt_bad_process(struct knote *kn, struct kevent_qos_s *kev); + +SECURITY_READ_ONLY_EARLY(static struct filterops) bad_filtops = { + .f_attach = filt_no_attach, + .f_detach = filt_no_detach, + .f_event = filt_bad_event, + .f_touch = filt_bad_touch, + .f_process = filt_bad_process, +}; + +#if CONFIG_MEMORYSTATUS +extern const struct filterops memorystatus_filtops; +#endif /* CONFIG_MEMORYSTATUS */ +extern const struct filterops fs_filtops; +extern const struct filterops sig_filtops; +extern const struct filterops machport_filtops; +extern const struct filterops pipe_nfiltops; +extern const struct filterops pipe_rfiltops; +extern const struct filterops pipe_wfiltops; +extern const struct filterops ptsd_kqops; +extern const struct filterops ptmx_kqops; +extern const struct filterops soread_filtops; +extern const struct filterops sowrite_filtops; +extern const struct filterops sock_filtops; +extern const struct filterops soexcept_filtops; +extern const struct filterops spec_filtops; +extern const struct filterops bpfread_filtops; +extern const struct filterops necp_fd_rfiltops; +extern const struct filterops fsevent_filtops; +extern const struct filterops vnode_filtops; +extern const struct filterops tty_filtops; + +const static struct filterops file_filtops; +const static struct filterops kqread_filtops; +const static struct filterops proc_filtops; +const static struct filterops timer_filtops; +const static struct filterops user_filtops; +const static struct filterops workloop_filtops; /* - * Install the protosw's for the NKE manager. Invoked at - * extension load time + * + * Rules for adding new filters to the system: + * Public filters: + * - Add a new "EVFILT_" option value to bsd/sys/event.h (typically a negative value) + * in the exported section of the header + * - Update the EVFILT_SYSCOUNT value to reflect the new addition + * - Add a filterops to the sysfilt_ops array. Public filters should be added at the end + * of the Public Filters section in the array. + * Private filters: + * - Add a new "EVFILT_" value to bsd/sys/event.h (typically a positive value) + * in the XNU_KERNEL_PRIVATE section of the header + * - Update the EVFILTID_MAX value to reflect the new addition + * - Add a filterops to the sysfilt_ops. Private filters should be added at the end of + * the Private filters section of the array. */ -int -kern_event_init(void) +static_assert(EVFILTID_MAX < UINT8_MAX, "kn_filtid expects this to be true"); +static const struct filterops * const sysfilt_ops[EVFILTID_MAX] = { + /* Public Filters */ + [~EVFILT_READ] = &file_filtops, + [~EVFILT_WRITE] = &file_filtops, + [~EVFILT_AIO] = &bad_filtops, + [~EVFILT_VNODE] = &file_filtops, + [~EVFILT_PROC] = &proc_filtops, + [~EVFILT_SIGNAL] = &sig_filtops, + [~EVFILT_TIMER] = &timer_filtops, + [~EVFILT_MACHPORT] = &machport_filtops, + [~EVFILT_FS] = &fs_filtops, + [~EVFILT_USER] = &user_filtops, + [~EVFILT_UNUSED_11] = &bad_filtops, + [~EVFILT_VM] = &bad_filtops, + [~EVFILT_SOCK] = &file_filtops, +#if CONFIG_MEMORYSTATUS + [~EVFILT_MEMORYSTATUS] = &memorystatus_filtops, +#else + [~EVFILT_MEMORYSTATUS] = &bad_filtops, +#endif + [~EVFILT_EXCEPT] = &file_filtops, + [~EVFILT_WORKLOOP] = &workloop_filtops, + + /* Private filters */ + [EVFILTID_KQREAD] = &kqread_filtops, + [EVFILTID_PIPE_N] = &pipe_nfiltops, + [EVFILTID_PIPE_R] = &pipe_rfiltops, + [EVFILTID_PIPE_W] = &pipe_wfiltops, + [EVFILTID_PTSD] = &ptsd_kqops, + [EVFILTID_SOREAD] = &soread_filtops, + [EVFILTID_SOWRITE] = &sowrite_filtops, + [EVFILTID_SCK] = &sock_filtops, + [EVFILTID_SOEXCEPT] = &soexcept_filtops, + [EVFILTID_SPEC] = &spec_filtops, + [EVFILTID_BPFREAD] = &bpfread_filtops, + [EVFILTID_NECP_FD] = &necp_fd_rfiltops, + [EVFILTID_FSEVENT] = &fsevent_filtops, + [EVFILTID_VN] = &vnode_filtops, + [EVFILTID_TTY] = &tty_filtops, + [EVFILTID_PTMX] = &ptmx_kqops, + + /* fake filter for detached knotes, keep last */ + [EVFILTID_DETACHED] = &bad_filtops, +}; + +/* waitq prepost callback */ +void waitq_set__CALLING_PREPOST_HOOK__(waitq_set_prepost_hook_t *kq_hook); + +static inline bool +kqr_thread_bound(workq_threadreq_t kqr) +{ + return kqr->tr_state == WORKQ_TR_STATE_BOUND; +} + +static inline bool +kqr_thread_requested_pending(workq_threadreq_t kqr) +{ + workq_tr_state_t tr_state = kqr->tr_state; + return tr_state > WORKQ_TR_STATE_IDLE && tr_state < WORKQ_TR_STATE_BOUND; +} + +static inline bool +kqr_thread_requested(workq_threadreq_t kqr) +{ + return kqr->tr_state != WORKQ_TR_STATE_IDLE; +} + +static inline thread_t +kqr_thread_fast(workq_threadreq_t kqr) +{ + assert(kqr_thread_bound(kqr)); + return kqr->tr_thread; +} + +static inline thread_t +kqr_thread(workq_threadreq_t kqr) +{ + return kqr_thread_bound(kqr) ? kqr->tr_thread : THREAD_NULL; +} + +static inline struct kqworkloop * +kqr_kqworkloop(workq_threadreq_t kqr) +{ + if (kqr->tr_flags & WORKQ_TR_FLAG_WORKLOOP) { + return __container_of(kqr, struct kqworkloop, kqwl_request); + } + return NULL; +} + +static inline kqueue_t +kqr_kqueue(proc_t p, workq_threadreq_t kqr) +{ + kqueue_t kqu; + if (kqr->tr_flags & WORKQ_TR_FLAG_WORKLOOP) { + kqu.kqwl = kqr_kqworkloop(kqr); + } else { + kqu.kqwq = p->p_fd->fd_wqkqueue; + assert(kqr >= kqu.kqwq->kqwq_request && + kqr < kqu.kqwq->kqwq_request + KQWQ_NBUCKETS); + } + return kqu; +} + +/* + * kqueue/note lock implementations + * + * The kqueue lock guards the kq state, the state of its queues, + * and the kqueue-aware status and locks of individual knotes. + * + * The kqueue workq lock is used to protect state guarding the + * interaction of the kqueue with the workq. This state cannot + * be guarded by the kq lock - as it needs to be taken when we + * already have the waitq set lock held (during the waitq hook + * callback). It might be better to use the waitq lock itself + * for this, but the IRQ requirements make that difficult). + * + * Knote flags, filter flags, and associated data are protected + * by the underlying object lock - and are only ever looked at + * by calling the filter to get a [consistent] snapshot of that + * data. + */ +static lck_grp_attr_t *kq_lck_grp_attr; +static lck_grp_t *kq_lck_grp; +static lck_attr_t *kq_lck_attr; + +static inline void +kqlock(kqueue_t kqu) +{ + lck_spin_lock(&kqu.kq->kq_lock); +} + +static inline void +kqlock_held(__assert_only kqueue_t kqu) +{ + LCK_SPIN_ASSERT(&kqu.kq->kq_lock, LCK_ASSERT_OWNED); +} + +static inline void +kqunlock(kqueue_t kqu) +{ + lck_spin_unlock(&kqu.kq->kq_lock); +} + +static inline void +knhash_lock(struct filedesc *fdp) +{ + lck_mtx_lock(&fdp->fd_knhashlock); +} + +static inline void +knhash_unlock(struct filedesc *fdp) +{ + lck_mtx_unlock(&fdp->fd_knhashlock); +} + +/* wait event for knote locks */ +static inline event_t +knote_lock_wev(struct knote *kn) +{ + return (event_t)(&kn->kn_hook); +} + +/* wait event for kevent_register_wait_* */ +static inline event64_t +knote_filt_wev64(struct knote *kn) +{ + /* kdp_workloop_sync_wait_find_owner knows about this */ + return CAST_EVENT64_T(kn); +} + +/* wait event for knote_post/knote_drop */ +static inline event64_t +knote_post_wev64(struct knote *kn) +{ + return CAST_EVENT64_T(&kn->kn_kevent); +} + +/*! + * @function knote_has_qos + * + * @brief + * Whether the knote has a regular QoS. + * + * @discussion + * kn_qos_override is: + * - 0 on kqfiles + * - THREAD_QOS_LAST for special buckets (stayactive, manager) + * + * Other values mean the knote participates to QoS propagation. + */ +static inline bool +knote_has_qos(struct knote *kn) +{ + return kn->kn_qos_override > 0 && kn->kn_qos_override < THREAD_QOS_LAST; +} + +#pragma mark knote locks + +/* + * Enum used by the knote_lock_* functions. + * + * KNOTE_KQ_LOCK_ALWAYS + * The function will always return with the kq lock held. + * + * KNOTE_KQ_LOCK_ON_SUCCESS + * The function will return with the kq lock held if it was successful + * (knote_lock() is the only function that can fail). + * + * KNOTE_KQ_LOCK_ON_FAILURE + * The function will return with the kq lock held if it was unsuccessful + * (knote_lock() is the only function that can fail). + * + * KNOTE_KQ_UNLOCK: + * The function returns with the kq unlocked. + */ +enum kqlocking { + KNOTE_KQ_LOCK_ALWAYS, + KNOTE_KQ_LOCK_ON_SUCCESS, + KNOTE_KQ_LOCK_ON_FAILURE, + KNOTE_KQ_UNLOCK, +}; + +static struct knote_lock_ctx * +knote_lock_ctx_find(kqueue_t kqu, struct knote *kn) +{ + struct knote_lock_ctx *ctx; + LIST_FOREACH(ctx, &kqu.kq->kq_knlocks, knlc_link) { + if (ctx->knlc_knote == kn) { + return ctx; + } + } + panic("knote lock context not found: %p", kn); + __builtin_trap(); +} + +/* slowpath of knote_lock() */ +__attribute__((noinline)) +static bool __result_use_check +knote_lock_slow(kqueue_t kqu, struct knote *kn, + struct knote_lock_ctx *knlc, int kqlocking) +{ + struct knote_lock_ctx *owner_lc; + struct uthread *uth = current_uthread(); + wait_result_t wr; + + kqlock_held(kqu); + + owner_lc = knote_lock_ctx_find(kqu, kn); +#if DEBUG || DEVELOPMENT + knlc->knlc_state = KNOTE_LOCK_CTX_WAITING; +#endif + owner_lc->knlc_waiters++; + + /* + * Make our lock context visible to knote_unlock() + */ + uth->uu_knlock = knlc; + + wr = lck_spin_sleep_with_inheritor(&kqu.kq->kq_lock, LCK_SLEEP_UNLOCK, + knote_lock_wev(kn), owner_lc->knlc_thread, + THREAD_UNINT | THREAD_WAIT_NOREPORT, TIMEOUT_WAIT_FOREVER); + + if (wr == THREAD_RESTART) { + /* + * We haven't been woken up by knote_unlock() but knote_unlock_cancel. + * We need to cleanup the state since no one did. + */ + uth->uu_knlock = NULL; +#if DEBUG || DEVELOPMENT + assert(knlc->knlc_state == KNOTE_LOCK_CTX_WAITING); + knlc->knlc_state = KNOTE_LOCK_CTX_UNLOCKED; +#endif + + if (kqlocking == KNOTE_KQ_LOCK_ALWAYS || + kqlocking == KNOTE_KQ_LOCK_ON_FAILURE) { + kqlock(kqu); + } + return false; + } else { + if (kqlocking == KNOTE_KQ_LOCK_ALWAYS || + kqlocking == KNOTE_KQ_LOCK_ON_SUCCESS) { + kqlock(kqu); +#if DEBUG || DEVELOPMENT + /* + * This state is set under the lock so we can't + * really assert this unless we hold the lock. + */ + assert(knlc->knlc_state == KNOTE_LOCK_CTX_LOCKED); +#endif + } + return true; + } +} + +/* + * Attempts to take the "knote" lock. + * + * Called with the kqueue lock held. + * + * Returns true if the knote lock is acquired, false if it has been dropped + */ +static bool __result_use_check +knote_lock(kqueue_t kqu, struct knote *kn, struct knote_lock_ctx *knlc, + enum kqlocking kqlocking) +{ + kqlock_held(kqu); + +#if DEBUG || DEVELOPMENT + assert(knlc->knlc_state == KNOTE_LOCK_CTX_UNLOCKED); +#endif + knlc->knlc_knote = kn; + knlc->knlc_thread = current_thread(); + knlc->knlc_waiters = 0; + + if (__improbable(kn->kn_status & KN_LOCKED)) { + return knote_lock_slow(kqu, kn, knlc, kqlocking); + } + + /* + * When the knote will be dropped, the knote lock is taken before + * KN_DROPPING is set, and then the knote will be removed from any + * hash table that references it before the lock is canceled. + */ + assert((kn->kn_status & KN_DROPPING) == 0); + LIST_INSERT_HEAD(&kqu.kq->kq_knlocks, knlc, knlc_link); + kn->kn_status |= KN_LOCKED; +#if DEBUG || DEVELOPMENT + knlc->knlc_state = KNOTE_LOCK_CTX_LOCKED; +#endif + + if (kqlocking == KNOTE_KQ_UNLOCK || + kqlocking == KNOTE_KQ_LOCK_ON_FAILURE) { + kqunlock(kqu); + } + return true; +} + +/* + * Unlocks a knote successfully locked with knote_lock(). + * + * Called with the kqueue lock held. + * + * Returns with the kqueue lock held according to KNOTE_KQ_* mode. + */ +static void +knote_unlock(kqueue_t kqu, struct knote *kn, + struct knote_lock_ctx *knlc, enum kqlocking kqlocking) +{ + kqlock_held(kqu); + + assert(knlc->knlc_knote == kn); + assert(kn->kn_status & KN_LOCKED); +#if DEBUG || DEVELOPMENT + assert(knlc->knlc_state == KNOTE_LOCK_CTX_LOCKED); +#endif + + LIST_REMOVE(knlc, knlc_link); + + if (knlc->knlc_waiters) { + thread_t thread = THREAD_NULL; + + wakeup_one_with_inheritor(knote_lock_wev(kn), THREAD_AWAKENED, + LCK_WAKE_DEFAULT, &thread); + + /* + * knote_lock_slow() publishes the lock context of waiters + * in uthread::uu_knlock. + * + * Reach out and make this context the new owner. + */ + struct uthread *ut = get_bsdthread_info(thread); + struct knote_lock_ctx *next_owner_lc = ut->uu_knlock; + + assert(next_owner_lc->knlc_knote == kn); + next_owner_lc->knlc_waiters = knlc->knlc_waiters - 1; + LIST_INSERT_HEAD(&kqu.kq->kq_knlocks, next_owner_lc, knlc_link); +#if DEBUG || DEVELOPMENT + next_owner_lc->knlc_state = KNOTE_LOCK_CTX_LOCKED; +#endif + ut->uu_knlock = NULL; + thread_deallocate_safe(thread); + } else { + kn->kn_status &= ~KN_LOCKED; + } + + if ((kn->kn_status & KN_MERGE_QOS) && !(kn->kn_status & KN_POSTING)) { + /* + * No f_event() in flight anymore, we can leave QoS "Merge" mode + * + * See knote_adjust_qos() + */ + kn->kn_status &= ~KN_MERGE_QOS; + } + if (kqlocking == KNOTE_KQ_UNLOCK) { + kqunlock(kqu); + } +#if DEBUG || DEVELOPMENT + knlc->knlc_state = KNOTE_LOCK_CTX_UNLOCKED; +#endif +} + +/* + * Aborts all waiters for a knote lock, and unlock the knote. + * + * Called with the kqueue lock held. + * + * Returns with the kqueue unlocked. + */ +static void +knote_unlock_cancel(struct kqueue *kq, struct knote *kn, + struct knote_lock_ctx *knlc) +{ + kqlock_held(kq); + + assert(knlc->knlc_knote == kn); + assert(kn->kn_status & KN_LOCKED); + assert(kn->kn_status & KN_DROPPING); + + LIST_REMOVE(knlc, knlc_link); + kn->kn_status &= ~KN_LOCKED; + kqunlock(kq); + + if (knlc->knlc_waiters) { + wakeup_all_with_inheritor(knote_lock_wev(kn), THREAD_RESTART); + } +#if DEBUG || DEVELOPMENT + knlc->knlc_state = KNOTE_LOCK_CTX_UNLOCKED; +#endif +} + +/* + * Call the f_event hook of a given filter. + * + * Takes a use count to protect against concurrent drops. + */ +static void +knote_post(struct knote *kn, long hint) +{ + struct kqueue *kq = knote_get_kq(kn); + int dropping, result; + + kqlock(kq); + + if (__improbable(kn->kn_status & (KN_DROPPING | KN_VANISHED))) { + return kqunlock(kq); + } + + if (__improbable(kn->kn_status & KN_POSTING)) { + panic("KNOTE() called concurrently on knote %p", kn); + } + + kn->kn_status |= KN_POSTING; + + kqunlock(kq); + result = filter_call(knote_fops(kn), f_event(kn, hint)); + kqlock(kq); + + dropping = (kn->kn_status & KN_DROPPING); + + if (!dropping && (result & FILTER_ACTIVE)) { + knote_activate(kq, kn, result); + } + + if ((kn->kn_status & KN_LOCKED) == 0) { + /* + * There's no other f_* call in flight, we can leave QoS "Merge" mode. + * + * See knote_adjust_qos() + */ + kn->kn_status &= ~(KN_POSTING | KN_MERGE_QOS); + } else { + kn->kn_status &= ~KN_POSTING; + } + + if (__improbable(dropping)) { + waitq_wakeup64_all((struct waitq *)&kq->kq_wqs, knote_post_wev64(kn), + THREAD_AWAKENED, WAITQ_ALL_PRIORITIES); + } + + kqunlock(kq); +} + +/* + * Called by knote_drop() to wait for the last f_event() caller to be done. + * + * - kq locked at entry + * - kq unlocked at exit + */ +static void +knote_wait_for_post(struct kqueue *kq, struct knote *kn) +{ + wait_result_t wr = THREAD_NOT_WAITING; + + kqlock_held(kq); + + assert(kn->kn_status & KN_DROPPING); + + if (kn->kn_status & KN_POSTING) { + wr = waitq_assert_wait64((struct waitq *)&kq->kq_wqs, + knote_post_wev64(kn), THREAD_UNINT | THREAD_WAIT_NOREPORT, + TIMEOUT_WAIT_FOREVER); + } + kqunlock(kq); + if (wr == THREAD_WAITING) { + thread_block(THREAD_CONTINUE_NULL); + } +} + +#pragma mark knote helpers for filters + +OS_ALWAYS_INLINE +void +knote_set_error(struct knote *kn, int error) +{ + kn->kn_flags |= EV_ERROR; + kn->kn_sdata = error; +} + +OS_ALWAYS_INLINE +int64_t +knote_low_watermark(const struct knote *kn) +{ + return (kn->kn_sfflags & NOTE_LOWAT) ? kn->kn_sdata : 1; +} + +/*! + * @function knote_fill_kevent_with_sdata + * + * @brief + * Fills in a kevent from the current content of a knote. + * + * @discussion + * This is meant to be called from filter's f_event hooks. + * The kevent data is filled with kn->kn_sdata. + * + * kn->kn_fflags is cleared if kn->kn_flags has EV_CLEAR set. + * + * Using knote_fill_kevent is typically preferred. + */ +OS_ALWAYS_INLINE +void +knote_fill_kevent_with_sdata(struct knote *kn, struct kevent_qos_s *kev) { - int retval; +#define knote_assert_aliases(name1, offs1, name2) \ + static_assert(offsetof(struct kevent_qos_s, name1) + offs1 == \ + offsetof(struct kevent_internal_s, name2), \ + "kevent_qos_s::" #name1 " and kevent_internal_s::" #name2 "need to alias") + /* + * All the code makes assumptions on these aliasing, + * so make sure we fail the build if we ever ever ever break them. + */ + knote_assert_aliases(ident, 0, kei_ident); +#ifdef __LITTLE_ENDIAN__ + knote_assert_aliases(filter, 0, kei_filter); // non trivial overlap + knote_assert_aliases(filter, 1, kei_filtid); // non trivial overlap +#else + knote_assert_aliases(filter, 0, kei_filtid); // non trivial overlap + knote_assert_aliases(filter, 1, kei_filter); // non trivial overlap +#endif + knote_assert_aliases(flags, 0, kei_flags); + knote_assert_aliases(qos, 0, kei_qos); + knote_assert_aliases(udata, 0, kei_udata); + knote_assert_aliases(fflags, 0, kei_fflags); + knote_assert_aliases(xflags, 0, kei_sfflags); // non trivial overlap + knote_assert_aliases(data, 0, kei_sdata); // non trivial overlap + knote_assert_aliases(ext, 0, kei_ext); +#undef knote_assert_aliases - if ((retval = net_add_proto(eventsw, &systemdomain)) == 0) - return(KERN_SUCCESS); - - log(LOG_WARNING, "Can't install kernel events protocol (%d)\n", retval); - return(retval); + /* + * Fix the differences between kevent_qos_s and kevent_internal_s: + * - xflags is where kn_sfflags lives, we need to zero it + * - fixup the high bits of `filter` where kn_filtid lives + */ + *kev = *(struct kevent_qos_s *)&kn->kn_kevent; + kev->xflags = 0; + kev->filter |= 0xff00; + if (kn->kn_flags & EV_CLEAR) { + kn->kn_fflags = 0; + } +} + +/*! + * @function knote_fill_kevent + * + * @brief + * Fills in a kevent from the current content of a knote. + * + * @discussion + * This is meant to be called from filter's f_event hooks. + * The kevent data is filled with the passed in data. + * + * kn->kn_fflags is cleared if kn->kn_flags has EV_CLEAR set. + */ +OS_ALWAYS_INLINE +void +knote_fill_kevent(struct knote *kn, struct kevent_qos_s *kev, int64_t data) +{ + knote_fill_kevent_with_sdata(kn, kev); + kev->filter = kn->kn_filter; + kev->data = data; } -int kev_attach(struct socket *so, int proto, struct proc *p) + +#pragma mark file_filtops + +static int +filt_fileattach(struct knote *kn, struct kevent_qos_s *kev) { - int error; - struct kern_event_pcb *ev_pcb; + return fo_kqfilter(kn->kn_fp, kn, kev); +} + +SECURITY_READ_ONLY_EARLY(static struct filterops) file_filtops = { + .f_isfd = 1, + .f_attach = filt_fileattach, +}; - ev_pcb = _MALLOC(sizeof(struct kern_event_pcb), M_PCB, M_WAITOK); - if (ev_pcb == 0) - return ENOBUFS; +#pragma mark kqread_filtops - ev_pcb->ev_socket = so; - ev_pcb->vendor_code_filter = 0xffffffff; +#define f_flag f_fglob->fg_flag +#define f_ops f_fglob->fg_ops +#define f_data f_fglob->fg_data +#define f_lflags f_fglob->fg_lflags - so->so_pcb = (caddr_t) ev_pcb; - LIST_INSERT_HEAD(&kern_event_head, ev_pcb, ev_link); - error = soreserve(so, KEV_SNDSPACE, KEV_RECVSPACE); - if (error) - return error; +static void +filt_kqdetach(struct knote *kn) +{ + struct kqfile *kqf = (struct kqfile *)kn->kn_fp->f_data; + struct kqueue *kq = &kqf->kqf_kqueue; + + kqlock(kq); + KNOTE_DETACH(&kqf->kqf_sel.si_note, kn); + kqunlock(kq); +} + +static int +filt_kqueue(struct knote *kn, __unused long hint) +{ + struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; - return 0; + return kq->kq_count > 0; } +static int +filt_kqtouch(struct knote *kn, struct kevent_qos_s *kev) +{ +#pragma unused(kev) + struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; + int res; + + kqlock(kq); + res = (kq->kq_count > 0); + kqunlock(kq); + + return res; +} -int kev_detach(struct socket *so) +static int +filt_kqprocess(struct knote *kn, struct kevent_qos_s *kev) { - struct kern_event_pcb *ev_pcb = (struct kern_event_pcb *) so->so_pcb; + struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; + int res = 0; - LIST_REMOVE(ev_pcb, ev_link); - if (ev_pcb) - FREE(ev_pcb, M_PCB); + kqlock(kq); + if (kq->kq_count) { + knote_fill_kevent(kn, kev, kq->kq_count); + res = 1; + } + kqunlock(kq); - return 0; + return res; } +SECURITY_READ_ONLY_EARLY(static struct filterops) kqread_filtops = { + .f_isfd = 1, + .f_detach = filt_kqdetach, + .f_event = filt_kqueue, + .f_touch = filt_kqtouch, + .f_process = filt_kqprocess, +}; + +#pragma mark proc_filtops -int kev_post_msg(struct kev_msg *event_msg) +static int +filt_procattach(struct knote *kn, __unused struct kevent_qos_s *kev) { - struct mbuf *m, *m2; - struct kern_event_pcb *ev_pcb; - struct kern_event_msg *ev; - char *tmp; - int total_size; - int i; + struct proc *p; + + assert(PID_MAX < NOTE_PDATAMASK); + if ((kn->kn_sfflags & (NOTE_TRACK | NOTE_TRACKERR | NOTE_CHILD)) != 0) { + knote_set_error(kn, ENOTSUP); + return 0; + } - m = m_get(M_DONTWAIT, MT_DATA); - if (m == 0) - return ENOBUFS; + p = proc_find(kn->kn_id); + if (p == NULL) { + knote_set_error(kn, ESRCH); + return 0; + } - ev = mtod(m, struct kern_event_msg *); - total_size = KEV_MSG_HEADER_SIZE; + const uint32_t NoteExitStatusBits = NOTE_EXIT | NOTE_EXITSTATUS; - tmp = (char *) &ev->event_data[0]; - for (i = 0; i < 5; i++) { - if (event_msg->dv[i].data_length == 0) - break; + if ((kn->kn_sfflags & NoteExitStatusBits) == NoteExitStatusBits) { + do { + pid_t selfpid = proc_selfpid(); - total_size += event_msg->dv[i].data_length; - bcopy(event_msg->dv[i].data_ptr, tmp, - event_msg->dv[i].data_length); - tmp += event_msg->dv[i].data_length; - } + if (p->p_ppid == selfpid) { + break; /* parent => ok */ + } + if ((p->p_lflag & P_LTRACED) != 0 && + (p->p_oppid == selfpid)) { + break; /* parent-in-waiting => ok */ + } + proc_rele(p); + knote_set_error(kn, EACCES); + return 0; + } while (0); + } + kn->kn_proc = p; + kn->kn_flags |= EV_CLEAR; /* automatically set */ + kn->kn_sdata = 0; /* incoming data is ignored */ - ev->id = ++static_event_id; - ev->total_size = total_size; - ev->vendor_code = event_msg->vendor_code; - ev->kev_class = event_msg->kev_class; - ev->kev_subclass = event_msg->kev_subclass; - ev->event_code = event_msg->event_code; + proc_klist_lock(); - m->m_len = total_size; - for (ev_pcb = LIST_FIRST(&kern_event_head); - ev_pcb; - ev_pcb = LIST_NEXT(ev_pcb, ev_link)) { + KNOTE_ATTACH(&p->p_klist, kn); - if (ev_pcb->vendor_code_filter != KEV_ANY_VENDOR) { - if (ev_pcb->vendor_code_filter != ev->vendor_code) - continue; + proc_klist_unlock(); - if (ev_pcb->class_filter != KEV_ANY_CLASS) { - if (ev_pcb->class_filter != ev->kev_class) - continue; + proc_rele(p); + + /* + * only captures edge-triggered events after this point + * so it can't already be fired. + */ + return 0; +} - if ((ev_pcb->subclass_filter != KEV_ANY_SUBCLASS) && - (ev_pcb->subclass_filter != ev->kev_subclass)) - continue; - } - } - m2 = m_copym(m, 0, m->m_len, M_NOWAIT); - if (m2 == 0) { - m_free(m); - return ENOBUFS; - } +/* + * The knote may be attached to a different process, which may exit, + * leaving nothing for the knote to be attached to. In that case, + * the pointer to the process will have already been nulled out. + */ +static void +filt_procdetach(struct knote *kn) +{ + struct proc *p; - sbappendrecord(&ev_pcb->ev_socket->so_rcv, m2); - sorwakeup(ev_pcb->ev_socket); - } + proc_klist_lock(); + p = kn->kn_proc; + if (p != PROC_NULL) { + kn->kn_proc = PROC_NULL; + KNOTE_DETACH(&p->p_klist, kn); + } - m_free(m); - return 0; + proc_klist_unlock(); } +static int +filt_procevent(struct knote *kn, long hint) +{ + u_int event; + + /* ALWAYS CALLED WITH proc_klist_lock */ + + /* + * Note: a lot of bits in hint may be obtained from the knote + * To free some of those bits, see Freeing up + * bits in hint for filt_procevent + * + * mask off extra data + */ + event = (u_int)hint & NOTE_PCTRLMASK; + + /* + * termination lifecycle events can happen while a debugger + * has reparented a process, in which case notifications + * should be quashed except to the tracing parent. When + * the debugger reaps the child (either via wait4(2) or + * process exit), the child will be reparented to the original + * parent and these knotes re-fired. + */ + if (event & NOTE_EXIT) { + if ((kn->kn_proc->p_oppid != 0) + && (knote_get_kq(kn)->kq_p->p_pid != kn->kn_proc->p_ppid)) { + /* + * This knote is not for the current ptrace(2) parent, ignore. + */ + return 0; + } + } + + /* + * if the user is interested in this event, record it. + */ + if (kn->kn_sfflags & event) { + kn->kn_fflags |= event; + } + +#pragma clang diagnostic push +#pragma clang diagnostic ignored "-Wdeprecated-declarations" + if ((event == NOTE_REAP) || ((event == NOTE_EXIT) && !(kn->kn_sfflags & NOTE_REAP))) { + kn->kn_flags |= (EV_EOF | EV_ONESHOT); + } +#pragma clang diagnostic pop + -int kev_control(so, cmd, data, ifp, p) - struct socket *so; - u_long cmd; - caddr_t data; - register struct ifnet *ifp; - struct proc *p; + /* + * The kernel has a wrapper in place that returns the same data + * as is collected here, in kn_hook32. Any changes to how + * NOTE_EXITSTATUS and NOTE_EXIT_DETAIL are collected + * should also be reflected in the proc_pidnoteexit() wrapper. + */ + if (event == NOTE_EXIT) { + kn->kn_hook32 = 0; + if ((kn->kn_sfflags & NOTE_EXITSTATUS) != 0) { + kn->kn_fflags |= NOTE_EXITSTATUS; + kn->kn_hook32 |= (hint & NOTE_PDATAMASK); + } + if ((kn->kn_sfflags & NOTE_EXIT_DETAIL) != 0) { + kn->kn_fflags |= NOTE_EXIT_DETAIL; + if ((kn->kn_proc->p_lflag & + P_LTERM_DECRYPTFAIL) != 0) { + kn->kn_hook32 |= NOTE_EXIT_DECRYPTFAIL; + } + if ((kn->kn_proc->p_lflag & + P_LTERM_JETSAM) != 0) { + kn->kn_hook32 |= NOTE_EXIT_MEMORY; + switch (kn->kn_proc->p_lflag & P_JETSAM_MASK) { + case P_JETSAM_VMPAGESHORTAGE: + kn->kn_hook32 |= NOTE_EXIT_MEMORY_VMPAGESHORTAGE; + break; + case P_JETSAM_VMTHRASHING: + kn->kn_hook32 |= NOTE_EXIT_MEMORY_VMTHRASHING; + break; + case P_JETSAM_FCTHRASHING: + kn->kn_hook32 |= NOTE_EXIT_MEMORY_FCTHRASHING; + break; + case P_JETSAM_VNODE: + kn->kn_hook32 |= NOTE_EXIT_MEMORY_VNODE; + break; + case P_JETSAM_HIWAT: + kn->kn_hook32 |= NOTE_EXIT_MEMORY_HIWAT; + break; + case P_JETSAM_PID: + kn->kn_hook32 |= NOTE_EXIT_MEMORY_PID; + break; + case P_JETSAM_IDLEEXIT: + kn->kn_hook32 |= NOTE_EXIT_MEMORY_IDLE; + break; + } + } + if ((kn->kn_proc->p_csflags & + CS_KILLED) != 0) { + kn->kn_hook32 |= NOTE_EXIT_CSERROR; + } + } + } + + /* if we have any matching state, activate the knote */ + return kn->kn_fflags != 0; +} + +static int +filt_proctouch(struct knote *kn, struct kevent_qos_s *kev) { - struct kev_request *kev_req = (struct kev_request *) data; - int stat = 0; - struct kern_event_pcb *ev_pcb; - u_long *id_value = (u_long *) data; + int res; + + proc_klist_lock(); + /* accept new filter flags and mask off output events no long interesting */ + kn->kn_sfflags = kev->fflags; - switch (cmd) { + /* restrict the current results to the (smaller?) set of new interest */ + /* + * For compatibility with previous implementations, we leave kn_fflags + * as they were before. + */ + //kn->kn_fflags &= kn->kn_sfflags; - case SIOCGKEVID: - *id_value = static_event_id; - break; + res = (kn->kn_fflags != 0); - case SIOCSKEVFILT: - ev_pcb = (struct kern_event_pcb *) so->so_pcb; - ev_pcb->vendor_code_filter = kev_req->vendor_code; - ev_pcb->class_filter = kev_req->kev_class; - ev_pcb->subclass_filter = kev_req->kev_subclass; - break; + proc_klist_unlock(); - case SIOCGKEVFILT: - ev_pcb = (struct kern_event_pcb *) so->so_pcb; - kev_req->vendor_code = ev_pcb->vendor_code_filter; - kev_req->kev_class = ev_pcb->class_filter; - kev_req->kev_subclass = ev_pcb->subclass_filter; - break; + return res; +} - default: - return EOPNOTSUPP; - } +static int +filt_procprocess(struct knote *kn, struct kevent_qos_s *kev) +{ + int res = 0; - return 0; + proc_klist_lock(); + if (kn->kn_fflags) { + knote_fill_kevent(kn, kev, kn->kn_hook32); + kn->kn_hook32 = 0; + res = 1; + } + proc_klist_unlock(); + return res; } +SECURITY_READ_ONLY_EARLY(static struct filterops) proc_filtops = { + .f_attach = filt_procattach, + .f_detach = filt_procdetach, + .f_event = filt_procevent, + .f_touch = filt_proctouch, + .f_process = filt_procprocess, +}; + +#pragma mark timer_filtops -struct pr_usrreqs event_usrreqs = { - pru_abort_notsupp, pru_accept_notsupp, kev_attach, pru_bind_notsupp, pru_connect_notsupp, - pru_connect2_notsupp, kev_control, kev_detach, pru_disconnect_notsupp, - pru_listen_notsupp, pru_peeraddr_notsupp, pru_rcvd_notsupp, pru_rcvoob_notsupp, - pru_send_notsupp, pru_sense_null, pru_shutdown_notsupp, pru_sockaddr_notsupp, - pru_sosend_notsupp, soreceive, sopoll +struct filt_timer_params { + uint64_t deadline; /* deadline in abs/cont time + * (or 0 if NOTE_ABSOLUTE and deadline is in past) */ + uint64_t leeway; /* leeway in abstime, or 0 if none */ + uint64_t interval; /* interval in abstime or 0 if non-repeating timer */ }; +/* + * Values stored in the knote at rest (using Mach absolute time units) + * + * kn->kn_thcall where the thread_call object is stored + * kn->kn_ext[0] next deadline or 0 if immediate expiration + * kn->kn_ext[1] leeway value + * kn->kn_sdata interval timer: the interval + * absolute/deadline timer: 0 + * kn->kn_hook32 timer state + * + * TIMER_IDLE: + * The timer has either never been scheduled or been cancelled. + * It is safe to schedule a new one in this state. + * + * TIMER_ARMED: + * The timer has been scheduled + * + * TIMER_FIRED + * The timer has fired and an event needs to be delivered. + * When in this state, the callout may still be running. + * + * TIMER_IMMEDIATE + * The timer has fired at registration time, and the callout was never + * dispatched. + */ +#define TIMER_IDLE 0x0 +#define TIMER_ARMED 0x1 +#define TIMER_FIRED 0x2 +#define TIMER_IMMEDIATE 0x3 + +static void +filt_timer_set_params(struct knote *kn, struct filt_timer_params *params) +{ + kn->kn_ext[0] = params->deadline; + kn->kn_ext[1] = params->leeway; + kn->kn_sdata = params->interval; +} + +/* + * filt_timervalidate - process data from user + * + * Sets up the deadline, interval, and leeway from the provided user data + * + * Input: + * kn_sdata timer deadline or interval time + * kn_sfflags style of timer, unit of measurement + * + * Output: + * struct filter_timer_params to apply to the filter with + * filt_timer_set_params when changes are ready to be commited. + * + * Returns: + * EINVAL Invalid user data parameters + * ERANGE Various overflows with the parameters + * + * Called with timer filter lock held. + */ +static int +filt_timervalidate(const struct kevent_qos_s *kev, + struct filt_timer_params *params) +{ + /* + * There are 5 knobs that need to be chosen for a timer registration: + * + * A) Units of time (what is the time duration of the specified number) + * Absolute and interval take: + * NOTE_SECONDS, NOTE_USECONDS, NOTE_NSECONDS, NOTE_MACHTIME + * Defaults to milliseconds if not specified + * + * B) Clock epoch (what is the zero point of the specified number) + * For interval, there is none + * For absolute, defaults to the gettimeofday/calendar epoch + * With NOTE_MACHTIME, uses mach_absolute_time() + * With NOTE_MACHTIME and NOTE_MACH_CONTINUOUS_TIME, uses mach_continuous_time() + * + * C) The knote's behavior on delivery + * Interval timer causes the knote to arm for the next interval unless one-shot is set + * Absolute is a forced one-shot timer which deletes on delivery + * TODO: Add a way for absolute to be not forced one-shot + * + * D) Whether the time duration is relative to now or absolute + * Interval fires at now + duration when it is set up + * Absolute fires at now + difference between now walltime and passed in walltime + * With NOTE_MACHTIME it fires at an absolute MAT or MCT. + * + * E) Whether the timer continues to tick across sleep + * By default all three do not. + * For interval and absolute, NOTE_MACH_CONTINUOUS_TIME causes them to tick across sleep + * With NOTE_ABSOLUTE | NOTE_MACHTIME | NOTE_MACH_CONTINUOUS_TIME: + * expires when mach_continuous_time() is > the passed in value. + */ + + uint64_t multiplier; + + boolean_t use_abstime = FALSE; + + switch (kev->fflags & (NOTE_SECONDS | NOTE_USECONDS | NOTE_NSECONDS | NOTE_MACHTIME)) { + case NOTE_SECONDS: + multiplier = NSEC_PER_SEC; + break; + case NOTE_USECONDS: + multiplier = NSEC_PER_USEC; + break; + case NOTE_NSECONDS: + multiplier = 1; + break; + case NOTE_MACHTIME: + multiplier = 0; + use_abstime = TRUE; + break; + case 0: /* milliseconds (default) */ + multiplier = NSEC_PER_SEC / 1000; + break; + default: + return EINVAL; + } + + /* transform the leeway in kn_ext[1] to same time scale */ + if (kev->fflags & NOTE_LEEWAY) { + uint64_t leeway_abs; + + if (use_abstime) { + leeway_abs = (uint64_t)kev->ext[1]; + } else { + uint64_t leeway_ns; + if (os_mul_overflow((uint64_t)kev->ext[1], multiplier, &leeway_ns)) { + return ERANGE; + } + + nanoseconds_to_absolutetime(leeway_ns, &leeway_abs); + } + + params->leeway = leeway_abs; + } else { + params->leeway = 0; + } + + if (kev->fflags & NOTE_ABSOLUTE) { + uint64_t deadline_abs; + + if (use_abstime) { + deadline_abs = (uint64_t)kev->data; + } else { + uint64_t calendar_deadline_ns; + + if (os_mul_overflow((uint64_t)kev->data, multiplier, &calendar_deadline_ns)) { + return ERANGE; + } + + /* calendar_deadline_ns is in nanoseconds since the epoch */ + + clock_sec_t seconds; + clock_nsec_t nanoseconds; + + /* + * Note that the conversion through wall-time is only done once. + * + * If the relationship between MAT and gettimeofday changes, + * the underlying timer does not update. + * + * TODO: build a wall-time denominated timer_call queue + * and a flag to request DTRTing with wall-time timers + */ + clock_get_calendar_nanotime(&seconds, &nanoseconds); + + uint64_t calendar_now_ns = (uint64_t)seconds * NSEC_PER_SEC + nanoseconds; + + /* if deadline is in the future */ + if (calendar_now_ns < calendar_deadline_ns) { + uint64_t interval_ns = calendar_deadline_ns - calendar_now_ns; + uint64_t interval_abs; + + nanoseconds_to_absolutetime(interval_ns, &interval_abs); + + /* + * Note that the NOTE_MACH_CONTINUOUS_TIME flag here only + * causes the timer to keep ticking across sleep, but + * it does not change the calendar timebase. + */ + + if (kev->fflags & NOTE_MACH_CONTINUOUS_TIME) { + clock_continuoustime_interval_to_deadline(interval_abs, + &deadline_abs); + } else { + clock_absolutetime_interval_to_deadline(interval_abs, + &deadline_abs); + } + } else { + deadline_abs = 0; /* cause immediate expiration */ + } + } + + params->deadline = deadline_abs; + params->interval = 0; /* NOTE_ABSOLUTE is non-repeating */ + } else if (kev->data < 0) { + /* + * Negative interval timers fire immediately, once. + * + * Ideally a negative interval would be an error, but certain clients + * pass negative values on accident, and expect an event back. + * + * In the old implementation the timer would repeat with no delay + * N times until mach_absolute_time() + (N * interval) underflowed, + * then it would wait ~forever by accidentally arming a timer for the far future. + * + * We now skip the power-wasting hot spin phase and go straight to the idle phase. + */ + + params->deadline = 0; /* expire immediately */ + params->interval = 0; /* non-repeating */ + } else { + uint64_t interval_abs = 0; + + if (use_abstime) { + interval_abs = (uint64_t)kev->data; + } else { + uint64_t interval_ns; + if (os_mul_overflow((uint64_t)kev->data, multiplier, &interval_ns)) { + return ERANGE; + } + + nanoseconds_to_absolutetime(interval_ns, &interval_abs); + } + + uint64_t deadline = 0; + + if (kev->fflags & NOTE_MACH_CONTINUOUS_TIME) { + clock_continuoustime_interval_to_deadline(interval_abs, &deadline); + } else { + clock_absolutetime_interval_to_deadline(interval_abs, &deadline); + } + + params->deadline = deadline; + params->interval = interval_abs; + } + + return 0; +} + +/* + * filt_timerexpire - the timer callout routine + */ +static void +filt_timerexpire(void *knx, __unused void *spare) +{ + struct knote *kn = knx; + int v; + + if (os_atomic_cmpxchgv(&kn->kn_hook32, TIMER_ARMED, TIMER_FIRED, + &v, relaxed)) { + // our f_event always would say FILTER_ACTIVE, + // so be leaner and just do it. + struct kqueue *kq = knote_get_kq(kn); + kqlock(kq); + knote_activate(kq, kn, FILTER_ACTIVE); + kqunlock(kq); + } else { + /* + * From TIMER_ARMED, the only allowed transition are: + * - to TIMER_FIRED through the timer callout just above + * - to TIMER_IDLE due to filt_timercancel() which will wait for the + * timer callout (and any possible invocation of filt_timerexpire) to + * have finished before the state is changed again. + */ + assert(v == TIMER_IDLE); + } +} + +static void +filt_timercancel(struct knote *kn) +{ + if (os_atomic_xchg(&kn->kn_hook32, TIMER_IDLE, relaxed) == TIMER_ARMED) { + /* cancel the thread call and wait for any filt_timerexpire in flight */ + thread_call_cancel_wait(kn->kn_thcall); + } +} + +/* + * Does this deadline needs a timer armed for it, or has it expired? + */ +static bool +filt_timer_is_ready(struct knote *kn) +{ + uint64_t now, deadline = kn->kn_ext[0]; + + if (deadline == 0) { + return true; + } + + if (kn->kn_sfflags & NOTE_MACH_CONTINUOUS_TIME) { + now = mach_continuous_time(); + } else { + now = mach_absolute_time(); + } + return deadline <= now; +} + +/* + * Arm a timer + * + * It is the responsibility of the caller to make sure the timer call + * has completed or been cancelled properly prior to arming it. + */ +static void +filt_timerarm(struct knote *kn) +{ + uint64_t deadline = kn->kn_ext[0]; + uint64_t leeway = kn->kn_ext[1]; + + int filter_flags = kn->kn_sfflags; + unsigned int timer_flags = 0; + + assert(os_atomic_load(&kn->kn_hook32, relaxed) == TIMER_IDLE); + + if (filter_flags & NOTE_CRITICAL) { + timer_flags |= THREAD_CALL_DELAY_USER_CRITICAL; + } else if (filter_flags & NOTE_BACKGROUND) { + timer_flags |= THREAD_CALL_DELAY_USER_BACKGROUND; + } else { + timer_flags |= THREAD_CALL_DELAY_USER_NORMAL; + } + + if (filter_flags & NOTE_LEEWAY) { + timer_flags |= THREAD_CALL_DELAY_LEEWAY; + } + + if (filter_flags & NOTE_MACH_CONTINUOUS_TIME) { + timer_flags |= THREAD_CALL_CONTINUOUS; + } + + os_atomic_store(&kn->kn_hook32, TIMER_ARMED, relaxed); + thread_call_enter_delayed_with_leeway(kn->kn_thcall, NULL, + deadline, leeway, timer_flags); +} + +/* + * Allocate a thread call for the knote's lifetime, and kick off the timer. + */ +static int +filt_timerattach(struct knote *kn, struct kevent_qos_s *kev) +{ + thread_call_t callout; + struct filt_timer_params params; + int error; + + if ((error = filt_timervalidate(kev, ¶ms)) != 0) { + knote_set_error(kn, error); + return 0; + } + + callout = thread_call_allocate_with_options(filt_timerexpire, + (thread_call_param_t)kn, THREAD_CALL_PRIORITY_HIGH, + THREAD_CALL_OPTIONS_ONCE); + + if (NULL == callout) { + knote_set_error(kn, ENOMEM); + return 0; + } + + filt_timer_set_params(kn, ¶ms); + kn->kn_thcall = callout; + kn->kn_flags |= EV_CLEAR; + os_atomic_store(&kn->kn_hook32, TIMER_IDLE, relaxed); + + /* NOTE_ABSOLUTE implies EV_ONESHOT */ + if (kn->kn_sfflags & NOTE_ABSOLUTE) { + kn->kn_flags |= EV_ONESHOT; + } + + if (filt_timer_is_ready(kn)) { + os_atomic_store(&kn->kn_hook32, TIMER_IMMEDIATE, relaxed); + return FILTER_ACTIVE; + } else { + filt_timerarm(kn); + return 0; + } +} + +/* + * Shut down the timer if it's running, and free the callout. + */ +static void +filt_timerdetach(struct knote *kn) +{ + __assert_only boolean_t freed; + + /* + * Unconditionally cancel to make sure there can't be any filt_timerexpire() + * running anymore. + */ + thread_call_cancel_wait(kn->kn_thcall); + freed = thread_call_free(kn->kn_thcall); + assert(freed); +} + +/* + * filt_timertouch - update timer knote with new user input + * + * Cancel and restart the timer based on new user data. When + * the user picks up a knote, clear the count of how many timer + * pops have gone off (in kn_data). + */ +static int +filt_timertouch(struct knote *kn, struct kevent_qos_s *kev) +{ + struct filt_timer_params params; + uint32_t changed_flags = (kn->kn_sfflags ^ kev->fflags); + int error; + + if (changed_flags & NOTE_ABSOLUTE) { + kev->flags |= EV_ERROR; + kev->data = EINVAL; + return 0; + } + + if ((error = filt_timervalidate(kev, ¶ms)) != 0) { + kev->flags |= EV_ERROR; + kev->data = error; + return 0; + } + + /* capture the new values used to compute deadline */ + filt_timercancel(kn); + filt_timer_set_params(kn, ¶ms); + kn->kn_sfflags = kev->fflags; + + if (filt_timer_is_ready(kn)) { + os_atomic_store(&kn->kn_hook32, TIMER_IMMEDIATE, relaxed); + return FILTER_ACTIVE | FILTER_UPDATE_REQ_QOS; + } else { + filt_timerarm(kn); + return FILTER_UPDATE_REQ_QOS; + } +} + +/* + * filt_timerprocess - query state of knote and snapshot event data + * + * Determine if the timer has fired in the past, snapshot the state + * of the kevent for returning to user-space, and clear pending event + * counters for the next time. + */ +static int +filt_timerprocess(struct knote *kn, struct kevent_qos_s *kev) +{ + /* + * filt_timerprocess is serialized with any filter routine except for + * filt_timerexpire which atomically does a TIMER_ARMED -> TIMER_FIRED + * transition, and on success, activates the knote. + * + * Hence, we don't need atomic modifications of the state, only to peek at + * whether we see any of the "FIRED" state, and if we do, it is safe to + * do simple state machine transitions. + */ + switch (os_atomic_load(&kn->kn_hook32, relaxed)) { + case TIMER_IDLE: + case TIMER_ARMED: + /* + * This can happen if a touch resets a timer that had fired + * without being processed + */ + return 0; + } + + os_atomic_store(&kn->kn_hook32, TIMER_IDLE, relaxed); + + /* + * Copy out the interesting kevent state, + * but don't leak out the raw time calculations. + * + * TODO: potential enhancements - tell the user about: + * - deadline to which this timer thought it was expiring + * - return kn_sfflags in the fflags field so the client can know + * under what flags the timer fired + */ + knote_fill_kevent(kn, kev, 1); + kev->ext[0] = 0; + /* kev->ext[1] = 0; JMM - shouldn't we hide this too? */ + + if (kn->kn_sdata != 0) { + /* + * This is a 'repeating' timer, so we have to emit + * how many intervals expired between the arm + * and the process. + * + * A very strange style of interface, because + * this could easily be done in the client... + */ + + uint64_t now; + + if (kn->kn_sfflags & NOTE_MACH_CONTINUOUS_TIME) { + now = mach_continuous_time(); + } else { + now = mach_absolute_time(); + } + + uint64_t first_deadline = kn->kn_ext[0]; + uint64_t interval_abs = kn->kn_sdata; + uint64_t orig_arm_time = first_deadline - interval_abs; + + assert(now > orig_arm_time); + assert(now > first_deadline); + + uint64_t elapsed = now - orig_arm_time; + + uint64_t num_fired = elapsed / interval_abs; + + /* + * To reach this code, we must have seen the timer pop + * and be in repeating mode, so therefore it must have been + * more than 'interval' time since the attach or last + * successful touch. + */ + assert(num_fired > 0); + + /* report how many intervals have elapsed to the user */ + kev->data = (int64_t)num_fired; + + /* We only need to re-arm the timer if it's not about to be destroyed */ + if ((kn->kn_flags & EV_ONESHOT) == 0) { + /* fire at the end of the next interval */ + uint64_t new_deadline = first_deadline + num_fired * interval_abs; + + assert(new_deadline > now); + + kn->kn_ext[0] = new_deadline; + + /* + * This can't shortcut setting up the thread call, because + * knote_process deactivates EV_CLEAR knotes unconditionnally. + */ + filt_timerarm(kn); + } + } + + return FILTER_ACTIVE; +} + +SECURITY_READ_ONLY_EARLY(static struct filterops) timer_filtops = { + .f_extended_codes = true, + .f_attach = filt_timerattach, + .f_detach = filt_timerdetach, + .f_event = filt_bad_event, + .f_touch = filt_timertouch, + .f_process = filt_timerprocess, +}; + +#pragma mark user_filtops + +static int +filt_userattach(struct knote *kn, __unused struct kevent_qos_s *kev) +{ + if (kn->kn_sfflags & NOTE_TRIGGER) { + kn->kn_hook32 = FILTER_ACTIVE; + } else { + kn->kn_hook32 = 0; + } + return kn->kn_hook32; +} + +static int +filt_usertouch(struct knote *kn, struct kevent_qos_s *kev) +{ + uint32_t ffctrl; + int fflags; + + ffctrl = kev->fflags & NOTE_FFCTRLMASK; + fflags = kev->fflags & NOTE_FFLAGSMASK; + switch (ffctrl) { + case NOTE_FFNOP: + break; + case NOTE_FFAND: + kn->kn_sfflags &= fflags; + break; + case NOTE_FFOR: + kn->kn_sfflags |= fflags; + break; + case NOTE_FFCOPY: + kn->kn_sfflags = fflags; + break; + } + kn->kn_sdata = kev->data; + + if (kev->fflags & NOTE_TRIGGER) { + kn->kn_hook32 = FILTER_ACTIVE; + } + return (int)kn->kn_hook32; +} + +static int +filt_userprocess(struct knote *kn, struct kevent_qos_s *kev) +{ + int result = (int)kn->kn_hook32; + + if (result) { + /* EVFILT_USER returns the data that was passed in */ + knote_fill_kevent_with_sdata(kn, kev); + kev->fflags = kn->kn_sfflags; + if (kn->kn_flags & EV_CLEAR) { + /* knote_fill_kevent cleared kn_fflags */ + kn->kn_hook32 = 0; + } + } + + return result; +} + +SECURITY_READ_ONLY_EARLY(static struct filterops) user_filtops = { + .f_extended_codes = true, + .f_attach = filt_userattach, + .f_detach = filt_no_detach, + .f_event = filt_bad_event, + .f_touch = filt_usertouch, + .f_process = filt_userprocess, +}; + +#pragma mark workloop_filtops + +#define EPREEMPTDISABLED (-1) + +static inline void +filt_wllock(struct kqworkloop *kqwl) +{ + lck_spin_lock(&kqwl->kqwl_statelock); +} + +static inline void +filt_wlunlock(struct kqworkloop *kqwl) +{ + lck_spin_unlock(&kqwl->kqwl_statelock); +} + +/* + * Returns true when the interlock for the turnstile is the workqueue lock + * + * When this is the case, all turnstiles operations are delegated + * to the workqueue subsystem. + * + * This is required because kqueue_threadreq_bind_prepost only holds the + * workqueue lock but needs to move the inheritor from the workloop turnstile + * away from the creator thread, so that this now fulfilled request cannot be + * picked anymore by other threads. + */ +static inline bool +filt_wlturnstile_interlock_is_workq(struct kqworkloop *kqwl) +{ + return kqr_thread_requested_pending(&kqwl->kqwl_request); +} + +static void +filt_wlupdate_inheritor(struct kqworkloop *kqwl, struct turnstile *ts, + turnstile_update_flags_t flags) +{ + turnstile_inheritor_t inheritor = TURNSTILE_INHERITOR_NULL; + workq_threadreq_t kqr = &kqwl->kqwl_request; + + /* + * binding to the workq should always happen through + * workq_kern_threadreq_update_inheritor() + */ + assert(!filt_wlturnstile_interlock_is_workq(kqwl)); + + if ((inheritor = kqwl->kqwl_owner)) { + flags |= TURNSTILE_INHERITOR_THREAD; + } else if ((inheritor = kqr_thread(kqr))) { + flags |= TURNSTILE_INHERITOR_THREAD; + } + + turnstile_update_inheritor(ts, inheritor, flags); +} + +#define EVFILT_WORKLOOP_EFAULT_RETRY_COUNT 100 +#define FILT_WLATTACH 0 +#define FILT_WLTOUCH 1 +#define FILT_WLDROP 2 + +__result_use_check +static int +filt_wlupdate(struct kqworkloop *kqwl, struct knote *kn, + struct kevent_qos_s *kev, kq_index_t qos_index, int op) +{ + user_addr_t uaddr = CAST_USER_ADDR_T(kev->ext[EV_EXTIDX_WL_ADDR]); + workq_threadreq_t kqr = &kqwl->kqwl_request; + thread_t cur_owner, new_owner, extra_thread_ref = THREAD_NULL; + kq_index_t cur_override = THREAD_QOS_UNSPECIFIED; + int efault_retry = EVFILT_WORKLOOP_EFAULT_RETRY_COUNT; + int action = KQWL_UTQ_NONE, error = 0; + bool wl_inheritor_updated = false, needs_wake = false; + uint64_t kdata = kev->ext[EV_EXTIDX_WL_VALUE]; + uint64_t mask = kev->ext[EV_EXTIDX_WL_MASK]; + uint64_t udata = 0; + struct turnstile *ts = TURNSTILE_NULL; + + filt_wllock(kqwl); + +again: + new_owner = cur_owner = kqwl->kqwl_owner; + + /* + * Phase 1: + * + * If asked, load the uint64 value at the user provided address and compare + * it against the passed in mask and expected value. + * + * If NOTE_WL_DISCOVER_OWNER is specified, translate the loaded name as + * a thread reference. + * + * If NOTE_WL_END_OWNERSHIP is specified and the currently known owner is + * the current thread, then end ownership. + * + * Lastly decide whether we need to perform a QoS update. + */ + if (uaddr) { + /* + * Until exists, + * disabling preemption copyin forces any + * vm_fault we encounter to fail. + */ + error = copyin_atomic64(uaddr, &udata); + + /* + * If we get EFAULT, drop locks, and retry. + * If we still get an error report it, + * else assume the memory has been faulted + * and attempt to copyin under lock again. + */ + switch (error) { + case 0: + break; + case EFAULT: + if (efault_retry-- > 0) { + filt_wlunlock(kqwl); + error = copyin_atomic64(uaddr, &udata); + filt_wllock(kqwl); + if (error == 0) { + goto again; + } + } + /* FALLTHROUGH */ + default: + goto out; + } + + /* Update state as copied in. */ + kev->ext[EV_EXTIDX_WL_VALUE] = udata; + + if ((udata & mask) != (kdata & mask)) { + error = ESTALE; + } else if (kev->fflags & NOTE_WL_DISCOVER_OWNER) { + /* + * Decipher the owner port name, and translate accordingly. + * The low 2 bits were borrowed for other flags, so mask them off. + * + * Then attempt translation to a thread reference or fail. + */ + mach_port_name_t name = (mach_port_name_t)udata & ~0x3; + if (name != MACH_PORT_NULL) { + name = ipc_entry_name_mask(name); + extra_thread_ref = port_name_to_thread(name, + PORT_TO_THREAD_IN_CURRENT_TASK); + if (extra_thread_ref == THREAD_NULL) { + error = EOWNERDEAD; + goto out; + } + new_owner = extra_thread_ref; + } + } + } + + if ((kev->fflags & NOTE_WL_END_OWNERSHIP) && new_owner == current_thread()) { + new_owner = THREAD_NULL; + } + + if (error == 0) { + if ((kev->fflags & NOTE_WL_THREAD_REQUEST) && (kev->flags & EV_DELETE)) { + action = KQWL_UTQ_SET_QOS_INDEX; + } else if (qos_index && kqr->tr_kq_qos_index != qos_index) { + action = KQWL_UTQ_SET_QOS_INDEX; + } + + if (op == FILT_WLTOUCH) { + /* + * Save off any additional fflags/data we just accepted + * But only keep the last round of "update" bits we acted on which helps + * debugging a lot. + */ + kn->kn_sfflags &= ~NOTE_WL_UPDATES_MASK; + kn->kn_sfflags |= kev->fflags; + if (kev->fflags & NOTE_WL_SYNC_WAKE) { + needs_wake = (kn->kn_thread != THREAD_NULL); + } + } else if (op == FILT_WLDROP) { + if ((kn->kn_sfflags & (NOTE_WL_SYNC_WAIT | NOTE_WL_SYNC_WAKE)) == + NOTE_WL_SYNC_WAIT) { + /* + * When deleting a SYNC_WAIT knote that hasn't been woken up + * explicitly, issue a wake up. + */ + kn->kn_sfflags |= NOTE_WL_SYNC_WAKE; + needs_wake = (kn->kn_thread != THREAD_NULL); + } + } + } + + /* + * Phase 2: + * + * Commit ownership and QoS changes if any, possibly wake up waiters + */ + + if (cur_owner == new_owner && action == KQWL_UTQ_NONE && !needs_wake) { + goto out; + } + + kqlock(kqwl); + + /* If already tracked as servicer, don't track as owner */ + if (new_owner == kqr_thread(kqr)) { + new_owner = THREAD_NULL; + } + + if (cur_owner != new_owner) { + kqwl->kqwl_owner = new_owner; + if (new_owner == extra_thread_ref) { + /* we just transfered this ref to kqwl_owner */ + extra_thread_ref = THREAD_NULL; + } + cur_override = kqworkloop_override(kqwl); + + if (new_owner) { + /* override it before we drop the old */ + if (cur_override != THREAD_QOS_UNSPECIFIED) { + thread_add_kevent_override(new_owner, cur_override); + } + if (kqr_thread_requested_pending(kqr)) { + if (action == KQWL_UTQ_NONE) { + action = KQWL_UTQ_REDRIVE_EVENTS; + } + } + } else { + if (!kqr_thread_requested(kqr) && kqr->tr_kq_wakeup) { + if (action == KQWL_UTQ_NONE) { + action = KQWL_UTQ_REDRIVE_EVENTS; + } + } + } + } + + if (action != KQWL_UTQ_NONE) { + kqworkloop_update_threads_qos(kqwl, action, qos_index); + } + + ts = kqwl->kqwl_turnstile; + if (cur_owner != new_owner && ts) { + if (action == KQWL_UTQ_REDRIVE_EVENTS) { + /* + * Note that when action is KQWL_UTQ_REDRIVE_EVENTS, + * the code went through workq_kern_threadreq_initiate() + * and the workqueue has set the inheritor already + */ + assert(filt_wlturnstile_interlock_is_workq(kqwl)); + } else if (filt_wlturnstile_interlock_is_workq(kqwl)) { + workq_kern_threadreq_lock(kqwl->kqwl_p); + workq_kern_threadreq_update_inheritor(kqwl->kqwl_p, kqr, new_owner, + ts, TURNSTILE_IMMEDIATE_UPDATE); + workq_kern_threadreq_unlock(kqwl->kqwl_p); + if (!filt_wlturnstile_interlock_is_workq(kqwl)) { + /* + * If the workq is no longer the interlock, then + * workq_kern_threadreq_update_inheritor() has finished a bind + * and we need to fallback to the regular path. + */ + filt_wlupdate_inheritor(kqwl, ts, TURNSTILE_IMMEDIATE_UPDATE); + } + wl_inheritor_updated = true; + } else { + filt_wlupdate_inheritor(kqwl, ts, TURNSTILE_IMMEDIATE_UPDATE); + wl_inheritor_updated = true; + } + + /* + * We need a turnstile reference because we are dropping the interlock + * and the caller has not called turnstile_prepare. + */ + if (wl_inheritor_updated) { + turnstile_reference(ts); + } + } + + if (needs_wake && ts) { + waitq_wakeup64_thread(&ts->ts_waitq, knote_filt_wev64(kn), + kn->kn_thread, THREAD_AWAKENED); + if (op == FILT_WLATTACH || op == FILT_WLTOUCH) { + disable_preemption(); + error = EPREEMPTDISABLED; + } + } + + kqunlock(kqwl); + +out: + /* + * Phase 3: + * + * Unlock and cleanup various lingering references and things. + */ + filt_wlunlock(kqwl); + +#if CONFIG_WORKLOOP_DEBUG + KQWL_HISTORY_WRITE_ENTRY(kqwl, { + .updater = current_thread(), + .servicer = kqr_thread(kqr), /* Note: racy */ + .old_owner = cur_owner, + .new_owner = new_owner, + + .kev_ident = kev->ident, + .error = (int16_t)error, + .kev_flags = kev->flags, + .kev_fflags = kev->fflags, + + .kev_mask = mask, + .kev_value = kdata, + .in_value = udata, + }); +#endif // CONFIG_WORKLOOP_DEBUG + + if (wl_inheritor_updated) { + turnstile_update_inheritor_complete(ts, TURNSTILE_INTERLOCK_NOT_HELD); + turnstile_deallocate_safe(ts); + } + + if (cur_owner && new_owner != cur_owner) { + if (cur_override != THREAD_QOS_UNSPECIFIED) { + thread_drop_kevent_override(cur_owner); + } + thread_deallocate_safe(cur_owner); + } + if (extra_thread_ref) { + thread_deallocate_safe(extra_thread_ref); + } + return error; +} + +/* + * Remembers the last updated that came in from userspace for debugging reasons. + * - fflags is mirrored from the userspace kevent + * - ext[i, i != VALUE] is mirrored from the userspace kevent + * - ext[VALUE] is set to what the kernel loaded atomically + * - data is set to the error if any + */ +static inline void +filt_wlremember_last_update(struct knote *kn, struct kevent_qos_s *kev, + int error) +{ + kn->kn_fflags = kev->fflags; + kn->kn_sdata = error; + memcpy(kn->kn_ext, kev->ext, sizeof(kev->ext)); +} + +static int +filt_wlupdate_sync_ipc(struct kqworkloop *kqwl, struct knote *kn, + struct kevent_qos_s *kev, int op) +{ + uint64_t uaddr = kev->ext[EV_EXTIDX_WL_ADDR]; + uint64_t kdata = kev->ext[EV_EXTIDX_WL_VALUE]; + uint64_t mask = kev->ext[EV_EXTIDX_WL_MASK]; + uint64_t udata = 0; + int efault_retry = EVFILT_WORKLOOP_EFAULT_RETRY_COUNT; + int error = 0; + + if (op == FILT_WLATTACH) { + (void)kqueue_alloc_turnstile(&kqwl->kqwl_kqueue); + } else if (uaddr == 0) { + return 0; + } + + filt_wllock(kqwl); + +again: + + /* + * Do the debounce thing, the lock serializing the state is the knote lock. + */ + if (uaddr) { + /* + * Until exists, + * disabling preemption copyin forces any + * vm_fault we encounter to fail. + */ + error = copyin_atomic64(uaddr, &udata); + + /* + * If we get EFAULT, drop locks, and retry. + * If we still get an error report it, + * else assume the memory has been faulted + * and attempt to copyin under lock again. + */ + switch (error) { + case 0: + break; + case EFAULT: + if (efault_retry-- > 0) { + filt_wlunlock(kqwl); + error = copyin_atomic64(uaddr, &udata); + filt_wllock(kqwl); + if (error == 0) { + goto again; + } + } + /* FALLTHROUGH */ + default: + goto out; + } + + kev->ext[EV_EXTIDX_WL_VALUE] = udata; + kn->kn_ext[EV_EXTIDX_WL_VALUE] = udata; + + if ((udata & mask) != (kdata & mask)) { + error = ESTALE; + goto out; + } + } + + if (op == FILT_WLATTACH) { + error = filt_wlattach_sync_ipc(kn); + if (error == 0) { + disable_preemption(); + error = EPREEMPTDISABLED; + } + } + +out: + filt_wlunlock(kqwl); + return error; +} + +static int +filt_wlattach(struct knote *kn, struct kevent_qos_s *kev) +{ + struct kqueue *kq = knote_get_kq(kn); + struct kqworkloop *kqwl = (struct kqworkloop *)kq; + int error = 0, result = 0; + kq_index_t qos_index = 0; + + if (__improbable((kq->kq_state & KQ_WORKLOOP) == 0)) { + error = ENOTSUP; + goto out; + } + + uint32_t command = (kn->kn_sfflags & NOTE_WL_COMMANDS_MASK); + switch (command) { + case NOTE_WL_THREAD_REQUEST: + if (kn->kn_id != kqwl->kqwl_dynamicid) { + error = EINVAL; + goto out; + } + qos_index = _pthread_priority_thread_qos(kn->kn_qos); + if (qos_index == THREAD_QOS_UNSPECIFIED) { + error = ERANGE; + goto out; + } + if (kqwl->kqwl_request.tr_kq_qos_index) { + /* + * There already is a thread request, and well, you're only allowed + * one per workloop, so fail the attach. + */ + error = EALREADY; + goto out; + } + break; + case NOTE_WL_SYNC_WAIT: + case NOTE_WL_SYNC_WAKE: + if (kn->kn_id == kqwl->kqwl_dynamicid) { + error = EINVAL; + goto out; + } + if ((kn->kn_flags & EV_DISABLE) == 0) { + error = EINVAL; + goto out; + } + if (kn->kn_sfflags & NOTE_WL_END_OWNERSHIP) { + error = EINVAL; + goto out; + } + break; + + case NOTE_WL_SYNC_IPC: + if ((kn->kn_flags & EV_DISABLE) == 0) { + error = EINVAL; + goto out; + } + if (kn->kn_sfflags & (NOTE_WL_UPDATE_QOS | NOTE_WL_DISCOVER_OWNER)) { + error = EINVAL; + goto out; + } + break; + default: + error = EINVAL; + goto out; + } + + if (command == NOTE_WL_SYNC_IPC) { + error = filt_wlupdate_sync_ipc(kqwl, kn, kev, FILT_WLATTACH); + } else { + error = filt_wlupdate(kqwl, kn, kev, qos_index, FILT_WLATTACH); + } + + if (error == EPREEMPTDISABLED) { + error = 0; + result = FILTER_THREADREQ_NODEFEER; + } +out: + if (error) { + /* If userland wants ESTALE to be hidden, fail the attach anyway */ + if (error == ESTALE && (kn->kn_sfflags & NOTE_WL_IGNORE_ESTALE)) { + error = 0; + } + knote_set_error(kn, error); + return result; + } + if (command == NOTE_WL_SYNC_WAIT) { + return kevent_register_wait_prepare(kn, kev, result); + } + /* Just attaching the thread request successfully will fire it */ + if (command == NOTE_WL_THREAD_REQUEST) { + /* + * Thread Request knotes need an explicit touch to be active again, + * so delivering an event needs to also consume it. + */ + kn->kn_flags |= EV_CLEAR; + return result | FILTER_ACTIVE; + } + return result; +} + +static void __dead2 +filt_wlwait_continue(void *parameter, wait_result_t wr) +{ + struct _kevent_register *cont_args = parameter; + struct kqworkloop *kqwl = cont_args->kqwl; + + kqlock(kqwl); + if (filt_wlturnstile_interlock_is_workq(kqwl)) { + workq_kern_threadreq_lock(kqwl->kqwl_p); + turnstile_complete((uintptr_t)kqwl, &kqwl->kqwl_turnstile, NULL, TURNSTILE_WORKLOOPS); + workq_kern_threadreq_unlock(kqwl->kqwl_p); + } else { + turnstile_complete((uintptr_t)kqwl, &kqwl->kqwl_turnstile, NULL, TURNSTILE_WORKLOOPS); + } + kqunlock(kqwl); + + turnstile_cleanup(); + + if (wr == THREAD_INTERRUPTED) { + cont_args->kev.flags |= EV_ERROR; + cont_args->kev.data = EINTR; + } else if (wr != THREAD_AWAKENED) { + panic("Unexpected wait result: %d", wr); + } + + kevent_register_wait_return(cont_args); +} + +/* + * Called with the workloop mutex held, most of the time never returns as it + * calls filt_wlwait_continue through a continuation. + */ +static void __dead2 +filt_wlpost_register_wait(struct uthread *uth, struct knote *kn, + struct _kevent_register *cont_args) +{ + struct kqworkloop *kqwl = cont_args->kqwl; + workq_threadreq_t kqr = &kqwl->kqwl_request; + struct turnstile *ts; + bool workq_locked = false; + + kqlock_held(kqwl); + + if (filt_wlturnstile_interlock_is_workq(kqwl)) { + workq_kern_threadreq_lock(kqwl->kqwl_p); + workq_locked = true; + } + + ts = turnstile_prepare((uintptr_t)kqwl, &kqwl->kqwl_turnstile, + TURNSTILE_NULL, TURNSTILE_WORKLOOPS); + + if (workq_locked) { + workq_kern_threadreq_update_inheritor(kqwl->kqwl_p, + &kqwl->kqwl_request, kqwl->kqwl_owner, ts, + TURNSTILE_DELAYED_UPDATE); + if (!filt_wlturnstile_interlock_is_workq(kqwl)) { + /* + * if the interlock is no longer the workqueue lock, + * then we don't need to hold it anymore. + */ + workq_kern_threadreq_unlock(kqwl->kqwl_p); + workq_locked = false; + } + } + if (!workq_locked) { + /* + * If the interlock is the workloop's, then it's our responsibility to + * call update_inheritor, so just do it. + */ + filt_wlupdate_inheritor(kqwl, ts, TURNSTILE_DELAYED_UPDATE); + } + + thread_set_pending_block_hint(uth->uu_thread, kThreadWaitWorkloopSyncWait); + waitq_assert_wait64(&ts->ts_waitq, knote_filt_wev64(kn), + THREAD_ABORTSAFE, TIMEOUT_WAIT_FOREVER); + + if (workq_locked) { + workq_kern_threadreq_unlock(kqwl->kqwl_p); + } + + thread_t thread = kqwl->kqwl_owner ?: kqr_thread(kqr); + if (thread) { + thread_reference(thread); + } + + kevent_register_wait_block(ts, thread, filt_wlwait_continue, cont_args); +} + +/* called in stackshot context to report the thread responsible for blocking this thread */ +void +kdp_workloop_sync_wait_find_owner(__assert_only thread_t thread, + event64_t event, thread_waitinfo_t *waitinfo) +{ + struct knote *kn = (struct knote *)event; + assert(kdp_is_in_zone(kn, "knote zone")); + + assert(kn->kn_thread == thread); + + struct kqueue *kq = knote_get_kq(kn); + assert(kdp_is_in_zone(kq, "kqueue workloop zone")); + assert(kq->kq_state & KQ_WORKLOOP); + + struct kqworkloop *kqwl = (struct kqworkloop *)kq; + workq_threadreq_t kqr = &kqwl->kqwl_request; + + thread_t kqwl_owner = kqwl->kqwl_owner; + + if (kqwl_owner != THREAD_NULL) { + assert(kdp_is_in_zone(kqwl_owner, "threads")); + + waitinfo->owner = thread_tid(kqwl->kqwl_owner); + } else if (kqr_thread_requested_pending(kqr)) { + waitinfo->owner = STACKSHOT_WAITOWNER_THREQUESTED; + } else if (kqr->tr_state >= WORKQ_TR_STATE_BINDING) { + assert(kdp_is_in_zone(kqr->tr_thread, "threads")); + waitinfo->owner = thread_tid(kqr->tr_thread); + } else { + waitinfo->owner = 0; + } + + waitinfo->context = kqwl->kqwl_dynamicid; +} + +static void +filt_wldetach(struct knote *kn) +{ + if (kn->kn_sfflags & NOTE_WL_SYNC_IPC) { + filt_wldetach_sync_ipc(kn); + } else if (kn->kn_thread) { + kevent_register_wait_cleanup(kn); + } +} + +static int +filt_wlvalidate_kev_flags(struct knote *kn, struct kevent_qos_s *kev, + thread_qos_t *qos_index) +{ + uint32_t new_commands = kev->fflags & NOTE_WL_COMMANDS_MASK; + uint32_t sav_commands = kn->kn_sfflags & NOTE_WL_COMMANDS_MASK; + + if ((kev->fflags & NOTE_WL_DISCOVER_OWNER) && (kev->flags & EV_DELETE)) { + return EINVAL; + } + if (kev->fflags & NOTE_WL_UPDATE_QOS) { + if (kev->flags & EV_DELETE) { + return EINVAL; + } + if (sav_commands != NOTE_WL_THREAD_REQUEST) { + return EINVAL; + } + if (!(*qos_index = _pthread_priority_thread_qos(kev->qos))) { + return ERANGE; + } + } + + switch (new_commands) { + case NOTE_WL_THREAD_REQUEST: + /* thread requests can only update themselves */ + if (sav_commands != NOTE_WL_THREAD_REQUEST) { + return EINVAL; + } + break; + + case NOTE_WL_SYNC_WAIT: + if (kev->fflags & NOTE_WL_END_OWNERSHIP) { + return EINVAL; + } + goto sync_checks; + + case NOTE_WL_SYNC_WAKE: +sync_checks: + if (!(sav_commands & (NOTE_WL_SYNC_WAIT | NOTE_WL_SYNC_WAKE))) { + return EINVAL; + } + if ((kev->flags & (EV_ENABLE | EV_DELETE)) == EV_ENABLE) { + return EINVAL; + } + break; + + case NOTE_WL_SYNC_IPC: + if (sav_commands != NOTE_WL_SYNC_IPC) { + return EINVAL; + } + if ((kev->flags & (EV_ENABLE | EV_DELETE)) == EV_ENABLE) { + return EINVAL; + } + break; + + default: + return EINVAL; + } + return 0; +} + +static int +filt_wltouch(struct knote *kn, struct kevent_qos_s *kev) +{ + struct kqworkloop *kqwl = (struct kqworkloop *)knote_get_kq(kn); + thread_qos_t qos_index = THREAD_QOS_UNSPECIFIED; + int result = 0; + + int error = filt_wlvalidate_kev_flags(kn, kev, &qos_index); + if (error) { + goto out; + } + + uint32_t command = kev->fflags & NOTE_WL_COMMANDS_MASK; + if (command == NOTE_WL_SYNC_IPC) { + error = filt_wlupdate_sync_ipc(kqwl, kn, kev, FILT_WLTOUCH); + } else { + error = filt_wlupdate(kqwl, kn, kev, qos_index, FILT_WLTOUCH); + filt_wlremember_last_update(kn, kev, error); + } + if (error == EPREEMPTDISABLED) { + error = 0; + result = FILTER_THREADREQ_NODEFEER; + } + +out: + if (error) { + if (error == ESTALE && (kev->fflags & NOTE_WL_IGNORE_ESTALE)) { + /* If userland wants ESTALE to be hidden, do not activate */ + return result; + } + kev->flags |= EV_ERROR; + kev->data = error; + return result; + } + if (command == NOTE_WL_SYNC_WAIT && !(kn->kn_sfflags & NOTE_WL_SYNC_WAKE)) { + return kevent_register_wait_prepare(kn, kev, result); + } + /* Just touching the thread request successfully will fire it */ + if (command == NOTE_WL_THREAD_REQUEST) { + if (kev->fflags & NOTE_WL_UPDATE_QOS) { + result |= FILTER_UPDATE_REQ_QOS; + } + result |= FILTER_ACTIVE; + } + return result; +} + +static bool +filt_wlallow_drop(struct knote *kn, struct kevent_qos_s *kev) +{ + struct kqworkloop *kqwl = (struct kqworkloop *)knote_get_kq(kn); + + int error = filt_wlvalidate_kev_flags(kn, kev, NULL); + if (error) { + goto out; + } + + uint32_t command = (kev->fflags & NOTE_WL_COMMANDS_MASK); + if (command == NOTE_WL_SYNC_IPC) { + error = filt_wlupdate_sync_ipc(kqwl, kn, kev, FILT_WLDROP); + } else { + error = filt_wlupdate(kqwl, kn, kev, 0, FILT_WLDROP); + filt_wlremember_last_update(kn, kev, error); + } + assert(error != EPREEMPTDISABLED); + +out: + if (error) { + if (error == ESTALE && (kev->fflags & NOTE_WL_IGNORE_ESTALE)) { + return false; + } + kev->flags |= EV_ERROR; + kev->data = error; + return false; + } + return true; +} + +static int +filt_wlprocess(struct knote *kn, struct kevent_qos_s *kev) +{ + struct kqworkloop *kqwl = (struct kqworkloop *)knote_get_kq(kn); + int rc = 0; + + assert(kn->kn_sfflags & NOTE_WL_THREAD_REQUEST); + + kqlock(kqwl); + + if (kqwl->kqwl_owner) { + /* + * userspace sometimes due to events being + * delivered but not triggering a drain session can cause a process + * of the thread request knote. + * + * When that happens, the automatic deactivation due to process + * would swallow the event, so we have to activate the knote again. + */ + knote_activate(kqwl, kn, FILTER_ACTIVE); + } else { +#if DEBUG || DEVELOPMENT + if (kevent_debug_flags() & KEVENT_PANIC_ON_NON_ENQUEUED_PROCESS) { + /* + * see src/queue_internal.h in libdispatch + */ +#define DISPATCH_QUEUE_ENQUEUED 0x1ull + user_addr_t addr = CAST_USER_ADDR_T(kn->kn_ext[EV_EXTIDX_WL_ADDR]); + task_t t = current_task(); + uint64_t val; + if (addr && task_is_active(t) && !task_is_halting(t) && + copyin_atomic64(addr, &val) == 0 && + val && (val & DISPATCH_QUEUE_ENQUEUED) == 0 && + (val >> 48) != 0xdead && (val >> 48) != 0 && (val >> 48) != 0xffff) { + panic("kevent: workloop %#016llx is not enqueued " + "(kn:%p dq_state:%#016llx kev.dq_state:%#016llx)", + kn->kn_udata, kn, val, kn->kn_ext[EV_EXTIDX_WL_VALUE]); + } + } +#endif + knote_fill_kevent(kn, kev, 0); + kev->fflags = kn->kn_sfflags; + rc |= FILTER_ACTIVE; + } + + kqunlock(kqwl); + + if (rc & FILTER_ACTIVE) { + workq_thread_set_max_qos(kqwl->kqwl_p, &kqwl->kqwl_request); + } + return rc; +} + +SECURITY_READ_ONLY_EARLY(static struct filterops) workloop_filtops = { + .f_extended_codes = true, + .f_attach = filt_wlattach, + .f_detach = filt_wldetach, + .f_event = filt_bad_event, + .f_touch = filt_wltouch, + .f_process = filt_wlprocess, + .f_allow_drop = filt_wlallow_drop, + .f_post_register_wait = filt_wlpost_register_wait, +}; + +#pragma mark - kqueues allocation and deallocation + +/*! + * @enum kqworkloop_dealloc_flags_t + * + * @brief + * Flags that alter kqworkloop_dealloc() behavior. + * + * @const KQWL_DEALLOC_NONE + * Convenient name for "no flags". + * + * @const KQWL_DEALLOC_SKIP_HASH_REMOVE + * Do not remove the workloop fromt he hash table. + * This is used for process tear-down codepaths as the workloops have been + * removed by the caller already. + */ +OS_OPTIONS(kqworkloop_dealloc_flags, unsigned, + KQWL_DEALLOC_NONE = 0x0000, + KQWL_DEALLOC_SKIP_HASH_REMOVE = 0x0001, + ); + +static void +kqworkloop_dealloc(struct kqworkloop *, kqworkloop_dealloc_flags_t, uint32_t); + +OS_NOINLINE OS_COLD OS_NORETURN +static void +kqworkloop_retain_panic(struct kqworkloop *kqwl, uint32_t previous) +{ + if (previous == 0) { + panic("kq(%p) resurrection", kqwl); + } else { + panic("kq(%p) retain overflow", kqwl); + } +} + +OS_NOINLINE OS_COLD OS_NORETURN +static void +kqworkloop_release_panic(struct kqworkloop *kqwl) +{ + panic("kq(%p) over-release", kqwl); +} + +OS_ALWAYS_INLINE +static inline bool +kqworkloop_try_retain(struct kqworkloop *kqwl) +{ + uint32_t old_ref, new_ref; + os_atomic_rmw_loop(&kqwl->kqwl_retains, old_ref, new_ref, relaxed, { + if (__improbable(old_ref == 0)) { + os_atomic_rmw_loop_give_up(return false); + } + if (__improbable(old_ref >= KQ_WORKLOOP_RETAINS_MAX)) { + kqworkloop_retain_panic(kqwl, old_ref); + } + new_ref = old_ref + 1; + }); + return true; +} + +OS_ALWAYS_INLINE +static inline void +kqworkloop_retain(struct kqworkloop *kqwl) +{ + uint32_t previous = os_atomic_inc_orig(&kqwl->kqwl_retains, relaxed); + if (__improbable(previous == 0 || previous >= KQ_WORKLOOP_RETAINS_MAX)) { + kqworkloop_retain_panic(kqwl, previous); + } +} + +OS_ALWAYS_INLINE +static inline void +kqueue_retain(kqueue_t kqu) +{ + if (kqu.kq->kq_state & KQ_DYNAMIC) { + kqworkloop_retain(kqu.kqwl); + } +} + +OS_ALWAYS_INLINE +static inline void +kqworkloop_release_live(struct kqworkloop *kqwl) +{ + uint32_t refs = os_atomic_dec_orig(&kqwl->kqwl_retains, relaxed); + if (__improbable(refs <= 1)) { + kqworkloop_release_panic(kqwl); + } +} + +OS_ALWAYS_INLINE +static inline void +kqueue_release_live(kqueue_t kqu) +{ + if (kqu.kq->kq_state & KQ_DYNAMIC) { + kqworkloop_release_live(kqu.kqwl); + } +} + +OS_ALWAYS_INLINE +static inline void +kqworkloop_release(struct kqworkloop *kqwl) +{ + uint32_t refs = os_atomic_dec_orig(&kqwl->kqwl_retains, relaxed); + + if (__improbable(refs <= 1)) { + kqworkloop_dealloc(kqwl, KQWL_DEALLOC_NONE, refs - 1); + } +} + +OS_ALWAYS_INLINE +static inline void +kqueue_release(kqueue_t kqu) +{ + if (kqu.kq->kq_state & KQ_DYNAMIC) { + kqworkloop_release(kqu.kqwl); + } +} + +/*! + * @function kqueue_destroy + * + * @brief + * Common part to all kqueue dealloc functions. + */ +OS_NOINLINE +static void +kqueue_destroy(kqueue_t kqu, zone_t zone) +{ + /* + * waitq_set_deinit() remove the KQ's waitq set from + * any select sets to which it may belong. + * + * The order of these deinits matter: before waitq_set_deinit() returns, + * waitq_set__CALLING_PREPOST_HOOK__ may be called and it will take the + * kq_lock. + */ + waitq_set_deinit(&kqu.kq->kq_wqs); + lck_spin_destroy(&kqu.kq->kq_lock, kq_lck_grp); + + zfree(zone, kqu.kq); +} + +/*! + * @function kqueue_init + * + * @brief + * Common part to all kqueue alloc functions. + */ +static kqueue_t +kqueue_init(kqueue_t kqu, waitq_set_prepost_hook_t *hook, int policy) +{ + waitq_set_init(&kqu.kq->kq_wqs, policy, NULL, hook); + lck_spin_init(&kqu.kq->kq_lock, kq_lck_grp, kq_lck_attr); + return kqu; +} + +#pragma mark kqfile allocation and deallocation + +/*! + * @function kqueue_dealloc + * + * @brief + * Detach all knotes from a kqfile and free it. + * + * @discussion + * We walk each list looking for knotes referencing this + * this kqueue. If we find one, we try to drop it. But + * if we fail to get a drop reference, that will wait + * until it is dropped. So, we can just restart again + * safe in the assumption that the list will eventually + * not contain any more references to this kqueue (either + * we dropped them all, or someone else did). + * + * Assumes no new events are being added to the kqueue. + * Nothing locked on entry or exit. + */ +void +kqueue_dealloc(struct kqueue *kq) +{ + KNOTE_LOCK_CTX(knlc); + struct proc *p = kq->kq_p; + struct filedesc *fdp = p->p_fd; + struct knote *kn; + + assert(kq && (kq->kq_state & (KQ_WORKLOOP | KQ_WORKQ)) == 0); + + proc_fdlock(p); + for (int i = 0; i < fdp->fd_knlistsize; i++) { + kn = SLIST_FIRST(&fdp->fd_knlist[i]); + while (kn != NULL) { + if (kq == knote_get_kq(kn)) { + kqlock(kq); + proc_fdunlock(p); + if (knote_lock(kq, kn, &knlc, KNOTE_KQ_LOCK_ON_SUCCESS)) { + knote_drop(kq, kn, &knlc); + } + proc_fdlock(p); + /* start over at beginning of list */ + kn = SLIST_FIRST(&fdp->fd_knlist[i]); + continue; + } + kn = SLIST_NEXT(kn, kn_link); + } + } + + knhash_lock(fdp); + proc_fdunlock(p); + + if (fdp->fd_knhashmask != 0) { + for (int i = 0; i < (int)fdp->fd_knhashmask + 1; i++) { + kn = SLIST_FIRST(&fdp->fd_knhash[i]); + while (kn != NULL) { + if (kq == knote_get_kq(kn)) { + kqlock(kq); + knhash_unlock(fdp); + if (knote_lock(kq, kn, &knlc, KNOTE_KQ_LOCK_ON_SUCCESS)) { + knote_drop(kq, kn, &knlc); + } + knhash_lock(fdp); + /* start over at beginning of list */ + kn = SLIST_FIRST(&fdp->fd_knhash[i]); + continue; + } + kn = SLIST_NEXT(kn, kn_link); + } + } + } + knhash_unlock(fdp); + + kqueue_destroy(kq, kqfile_zone); +} + +/*! + * @function kqueue_alloc + * + * @brief + * Allocate a kqfile. + */ +struct kqueue * +kqueue_alloc(struct proc *p) +{ + struct kqfile *kqf; + + kqf = (struct kqfile *)zalloc(kqfile_zone); + if (__improbable(kqf == NULL)) { + return NULL; + } + bzero(kqf, sizeof(struct kqfile)); + + /* + * kqfiles are created with kqueue() so we need to wait for + * the first kevent syscall to know which bit among + * KQ_KEV_{32,64,QOS} will be set in kqf_state + */ + kqf->kqf_p = p; + TAILQ_INIT_AFTER_BZERO(&kqf->kqf_queue); + TAILQ_INIT_AFTER_BZERO(&kqf->kqf_suppressed); + + return kqueue_init(kqf, NULL, SYNC_POLICY_FIFO | SYNC_POLICY_PREPOST).kq; +} + +/*! + * @function kqueue_internal + * + * @brief + * Core implementation for kqueue and guarded_kqueue_np() + */ +int +kqueue_internal(struct proc *p, fp_allocfn_t fp_zalloc, void *cra, int32_t *retval) +{ + struct kqueue *kq; + struct fileproc *fp; + int fd, error; + + error = falloc_withalloc(p, &fp, &fd, vfs_context_current(), fp_zalloc, cra); + if (error) { + return error; + } + + kq = kqueue_alloc(p); + if (kq == NULL) { + fp_free(p, fd, fp); + return ENOMEM; + } + + fp->f_flag = FREAD | FWRITE; + fp->f_ops = &kqueueops; + fp->f_data = kq; + fp->f_lflags |= FG_CONFINED; + + proc_fdlock(p); + *fdflags(p, fd) |= UF_EXCLOSE | UF_FORKCLOSE; + procfdtbl_releasefd(p, fd, NULL); + fp_drop(p, fd, fp, 1); + proc_fdunlock(p); + + *retval = fd; + return error; +} + +/*! + * @function kqueue + * + * @brief + * The kqueue syscall. + */ +int +kqueue(struct proc *p, __unused struct kqueue_args *uap, int32_t *retval) +{ + return kqueue_internal(p, fileproc_alloc_init, NULL, retval); +} + +#pragma mark kqworkq allocation and deallocation + +/*! + * @function kqworkq_dealloc + * + * @brief + * Deallocates a workqueue kqueue. + * + * @discussion + * This only happens at process death, or for races with concurrent + * kevent_get_kqwq calls, hence we don't have to care about knotes referencing + * this kqueue, either there are none, or someone else took care of them. + */ +void +kqworkq_dealloc(struct kqworkq *kqwq) +{ + kqueue_destroy(kqwq, kqworkq_zone); +} + +/*! + * @function kqworkq_alloc + * + * @brief + * Allocates a workqueue kqueue. + * + * @discussion + * This is the slow path of kevent_get_kqwq. + * This takes care of making sure procs have a single workq kqueue. + */ +OS_NOINLINE +static struct kqworkq * +kqworkq_alloc(struct proc *p, unsigned int flags) +{ + struct kqworkq *kqwq, *tmp; + + kqwq = (struct kqworkq *)zalloc(kqworkq_zone); + if (__improbable(kqwq == NULL)) { + return NULL; + } + bzero(kqwq, sizeof(struct kqworkq)); + + assert((flags & KEVENT_FLAG_LEGACY32) == 0); + if (flags & KEVENT_FLAG_LEGACY64) { + kqwq->kqwq_state = KQ_WORKQ | KQ_KEV64; + } else { + kqwq->kqwq_state = KQ_WORKQ | KQ_KEV_QOS; + } + kqwq->kqwq_p = p; + + for (int i = 0; i < KQWQ_NBUCKETS; i++) { + TAILQ_INIT_AFTER_BZERO(&kqwq->kqwq_queue[i]); + TAILQ_INIT_AFTER_BZERO(&kqwq->kqwq_suppressed[i]); + } + for (int i = 0; i < KQWQ_NBUCKETS; i++) { + /* + * Because of how the bucketized system works, we mix overcommit + * sources with not overcommit: each time we move a knote from + * one bucket to the next due to overrides, we'd had to track + * overcommitness, and it's really not worth it in the workloop + * enabled world that track this faithfully. + * + * Incidentally, this behaves like the original manager-based + * kqwq where event delivery always happened (hence is + * "overcommit") + */ + kqwq->kqwq_request[i].tr_state = WORKQ_TR_STATE_IDLE; + kqwq->kqwq_request[i].tr_flags = WORKQ_TR_FLAG_KEVENT; + if (i != KQWQ_QOS_MANAGER) { + kqwq->kqwq_request[i].tr_flags |= WORKQ_TR_FLAG_OVERCOMMIT; + } + kqwq->kqwq_request[i].tr_kq_qos_index = i; + } + + kqueue_init(kqwq, &kqwq->kqwq_waitq_hook, SYNC_POLICY_FIFO); + + if (!os_atomic_cmpxchgv(&p->p_fd->fd_wqkqueue, NULL, kqwq, &tmp, release)) { + kqworkq_dealloc(kqwq); + return tmp; + } + + return kqwq; +} + +#pragma mark kqworkloop allocation and deallocation + +#define KQ_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) +#define CONFIG_KQ_HASHSIZE CONFIG_KN_HASHSIZE + +OS_ALWAYS_INLINE +static inline void +kqhash_lock(struct filedesc *fdp) +{ + lck_mtx_lock_spin_always(&fdp->fd_kqhashlock); +} + +OS_ALWAYS_INLINE +static inline void +kqhash_unlock(struct filedesc *fdp) +{ + lck_mtx_unlock(&fdp->fd_kqhashlock); +} + +OS_ALWAYS_INLINE +static inline void +kqworkloop_hash_insert_locked(struct filedesc *fdp, kqueue_id_t id, + struct kqworkloop *kqwl) +{ + struct kqwllist *list = &fdp->fd_kqhash[KQ_HASH(id, fdp->fd_kqhashmask)]; + LIST_INSERT_HEAD(list, kqwl, kqwl_hashlink); +} + +OS_ALWAYS_INLINE +static inline struct kqworkloop * +kqworkloop_hash_lookup_locked(struct filedesc *fdp, kqueue_id_t id) +{ + struct kqwllist *list = &fdp->fd_kqhash[KQ_HASH(id, fdp->fd_kqhashmask)]; + struct kqworkloop *kqwl; + + LIST_FOREACH(kqwl, list, kqwl_hashlink) { + if (kqwl->kqwl_dynamicid == id) { + return kqwl; + } + } + return NULL; +} + +static struct kqworkloop * +kqworkloop_hash_lookup_and_retain(struct filedesc *fdp, kqueue_id_t kq_id) +{ + struct kqworkloop *kqwl = NULL; + + kqhash_lock(fdp); + if (__probable(fdp->fd_kqhash)) { + kqwl = kqworkloop_hash_lookup_locked(fdp, kq_id); + if (kqwl && !kqworkloop_try_retain(kqwl)) { + kqwl = NULL; + } + } + kqhash_unlock(fdp); + return kqwl; +} + +OS_NOINLINE +static void +kqworkloop_hash_init(struct filedesc *fdp) +{ + struct kqwllist *alloc_hash; + u_long alloc_mask; + + kqhash_unlock(fdp); + alloc_hash = hashinit(CONFIG_KQ_HASHSIZE, M_KQUEUE, &alloc_mask); + kqhash_lock(fdp); + + /* See if we won the race */ + if (__probable(fdp->fd_kqhashmask == 0)) { + fdp->fd_kqhash = alloc_hash; + fdp->fd_kqhashmask = alloc_mask; + } else { + kqhash_unlock(fdp); + FREE(alloc_hash, M_KQUEUE); + kqhash_lock(fdp); + } +} + +/*! + * @function kqworkloop_dealloc + * + * @brief + * Deallocates a workloop kqueue. + * + * @discussion + * Knotes hold references on the workloop, so we can't really reach this + * function unless all of these are already gone. + * + * Nothing locked on entry or exit. + * + * @param flags + * Unless KQWL_DEALLOC_SKIP_HASH_REMOVE is set, the workloop is removed + * from its hash table. + * + * @param current_ref + * This function is also called to undo a kqworkloop_alloc in case of + * allocation races, expected_ref is the current refcount that is expected + * on the workloop object, usually 0, and 1 when a dealloc race is resolved. + */ +static void +kqworkloop_dealloc(struct kqworkloop *kqwl, kqworkloop_dealloc_flags_t flags, + uint32_t current_ref) +{ + thread_t cur_owner; + + if (__improbable(current_ref > 1)) { + kqworkloop_release_panic(kqwl); + } + assert(kqwl->kqwl_retains == current_ref); + + /* pair with kqunlock() and other kq locks */ + os_atomic_thread_fence(acquire); + + cur_owner = kqwl->kqwl_owner; + if (cur_owner) { + if (kqworkloop_override(kqwl) != THREAD_QOS_UNSPECIFIED) { + thread_drop_kevent_override(cur_owner); + } + thread_deallocate(cur_owner); + kqwl->kqwl_owner = THREAD_NULL; + } + + if (kqwl->kqwl_state & KQ_HAS_TURNSTILE) { + struct turnstile *ts; + turnstile_complete((uintptr_t)kqwl, &kqwl->kqwl_turnstile, + &ts, TURNSTILE_WORKLOOPS); + turnstile_cleanup(); + turnstile_deallocate(ts); + } + + if ((flags & KQWL_DEALLOC_SKIP_HASH_REMOVE) == 0) { + struct filedesc *fdp = kqwl->kqwl_p->p_fd; + + kqhash_lock(fdp); + LIST_REMOVE(kqwl, kqwl_hashlink); + kqhash_unlock(fdp); + } + + assert(TAILQ_EMPTY(&kqwl->kqwl_suppressed)); + assert(kqwl->kqwl_owner == THREAD_NULL); + assert(kqwl->kqwl_turnstile == TURNSTILE_NULL); + + lck_spin_destroy(&kqwl->kqwl_statelock, kq_lck_grp); + kqueue_destroy(kqwl, kqworkloop_zone); +} + +/*! + * @function kqworkloop_alloc + * + * @brief + * Allocates a workloop kqueue. + */ +static void +kqworkloop_init(struct kqworkloop *kqwl, proc_t p, + kqueue_id_t id, workq_threadreq_param_t *trp) +{ + bzero(kqwl, sizeof(struct kqworkloop)); + + kqwl->kqwl_state = KQ_WORKLOOP | KQ_DYNAMIC | KQ_KEV_QOS; + kqwl->kqwl_retains = 1; /* donate a retain to creator */ + kqwl->kqwl_dynamicid = id; + kqwl->kqwl_p = p; + if (trp) { + kqwl->kqwl_params = trp->trp_value; + } + + workq_tr_flags_t tr_flags = WORKQ_TR_FLAG_WORKLOOP; + if (trp) { + if (trp->trp_flags & TRP_PRIORITY) { + tr_flags |= WORKQ_TR_FLAG_WL_OUTSIDE_QOS; + } + if (trp->trp_flags) { + tr_flags |= WORKQ_TR_FLAG_WL_PARAMS; + } + } + kqwl->kqwl_request.tr_state = WORKQ_TR_STATE_IDLE; + kqwl->kqwl_request.tr_flags = tr_flags; + + for (int i = 0; i < KQWL_NBUCKETS; i++) { + TAILQ_INIT_AFTER_BZERO(&kqwl->kqwl_queue[i]); + } + TAILQ_INIT_AFTER_BZERO(&kqwl->kqwl_suppressed); + + lck_spin_init(&kqwl->kqwl_statelock, kq_lck_grp, kq_lck_attr); + + kqueue_init(kqwl, &kqwl->kqwl_waitq_hook, SYNC_POLICY_FIFO); +} + +/*! + * @function kqworkloop_get_or_create + * + * @brief + * Wrapper around kqworkloop_alloc that handles the uniquing of workloops. + * + * @returns + * 0: success + * EINVAL: invalid parameters + * EEXIST: KEVENT_FLAG_DYNAMIC_KQ_MUST_NOT_EXIST is set and a collision exists. + * ENOENT: KEVENT_FLAG_DYNAMIC_KQ_MUST_EXIST is set and the entry wasn't found. + * ENOMEM: allocation failed + */ +static int +kqworkloop_get_or_create(struct proc *p, kqueue_id_t id, + workq_threadreq_param_t *trp, unsigned int flags, struct kqworkloop **kqwlp) +{ + struct filedesc *fdp = p->p_fd; + struct kqworkloop *alloc_kqwl = NULL; + struct kqworkloop *kqwl = NULL; + int error = 0; + + assert(!trp || (flags & KEVENT_FLAG_DYNAMIC_KQ_MUST_NOT_EXIST)); + + if (id == 0 || id == (kqueue_id_t)-1) { + return EINVAL; + } + + for (;;) { + kqhash_lock(fdp); + if (__improbable(fdp->fd_kqhash == NULL)) { + kqworkloop_hash_init(fdp); + } + + kqwl = kqworkloop_hash_lookup_locked(fdp, id); + if (kqwl) { + if (__improbable(flags & KEVENT_FLAG_DYNAMIC_KQ_MUST_NOT_EXIST)) { + /* + * If MUST_NOT_EXIST was passed, even if we would have failed + * the try_retain, it could have gone the other way, and + * userspace can't tell. Let'em fix their race. + */ + error = EEXIST; + break; + } + + if (__probable(kqworkloop_try_retain(kqwl))) { + /* + * This is a valid live workloop ! + */ + *kqwlp = kqwl; + error = 0; + break; + } + } + + if (__improbable(flags & KEVENT_FLAG_DYNAMIC_KQ_MUST_EXIST)) { + error = ENOENT; + break; + } + + /* + * We didn't find what we were looking for. + * + * If this is the second time we reach this point (alloc_kqwl != NULL), + * then we're done. + * + * If this is the first time we reach this point (alloc_kqwl == NULL), + * then try to allocate one without blocking. + */ + if (__probable(alloc_kqwl == NULL)) { + alloc_kqwl = (struct kqworkloop *)zalloc_noblock(kqworkloop_zone); + } + if (__probable(alloc_kqwl)) { + kqworkloop_init(alloc_kqwl, p, id, trp); + kqworkloop_hash_insert_locked(fdp, id, alloc_kqwl); + kqhash_unlock(fdp); + *kqwlp = alloc_kqwl; + return 0; + } + + /* + * We have to block to allocate a workloop, drop the lock, + * allocate one, but then we need to retry lookups as someone + * else could race with us. + */ + kqhash_unlock(fdp); + + alloc_kqwl = (struct kqworkloop *)zalloc(kqworkloop_zone); + if (__improbable(!alloc_kqwl)) { + return ENOMEM; + } + } + + kqhash_unlock(fdp); + + if (__improbable(alloc_kqwl)) { + zfree(kqworkloop_zone, alloc_kqwl); + } + + return error; +} + +#pragma mark - knotes + +static int +filt_no_attach(struct knote *kn, __unused struct kevent_qos_s *kev) +{ + knote_set_error(kn, ENOTSUP); + return 0; +} + +static void +filt_no_detach(__unused struct knote *kn) +{ +} + +static int __dead2 +filt_bad_event(struct knote *kn, long hint) +{ + panic("%s[%d](%p, %ld)", __func__, kn->kn_filter, kn, hint); +} + +static int __dead2 +filt_bad_touch(struct knote *kn, struct kevent_qos_s *kev) +{ + panic("%s[%d](%p, %p)", __func__, kn->kn_filter, kn, kev); +} + +static int __dead2 +filt_bad_process(struct knote *kn, struct kevent_qos_s *kev) +{ + panic("%s[%d](%p, %p)", __func__, kn->kn_filter, kn, kev); +} + +/* + * knotes_dealloc - detach all knotes for the process and drop them + * + * Called with proc_fdlock held. + * Returns with it locked. + * May drop it temporarily. + * Process is in such a state that it will not try to allocate + * any more knotes during this process (stopped for exit or exec). + */ +void +knotes_dealloc(proc_t p) +{ + struct filedesc *fdp = p->p_fd; + struct kqueue *kq; + struct knote *kn; + struct klist *kn_hash = NULL; + int i; + + /* Close all the fd-indexed knotes up front */ + if (fdp->fd_knlistsize > 0) { + for (i = 0; i < fdp->fd_knlistsize; i++) { + while ((kn = SLIST_FIRST(&fdp->fd_knlist[i])) != NULL) { + kq = knote_get_kq(kn); + kqlock(kq); + proc_fdunlock(p); + knote_drop(kq, kn, NULL); + proc_fdlock(p); + } + } + /* free the table */ + FREE(fdp->fd_knlist, M_KQUEUE); + fdp->fd_knlist = NULL; + } + fdp->fd_knlistsize = 0; + + knhash_lock(fdp); + proc_fdunlock(p); + + /* Clean out all the hashed knotes as well */ + if (fdp->fd_knhashmask != 0) { + for (i = 0; i <= (int)fdp->fd_knhashmask; i++) { + while ((kn = SLIST_FIRST(&fdp->fd_knhash[i])) != NULL) { + kq = knote_get_kq(kn); + kqlock(kq); + knhash_unlock(fdp); + knote_drop(kq, kn, NULL); + knhash_lock(fdp); + } + } + kn_hash = fdp->fd_knhash; + fdp->fd_knhashmask = 0; + fdp->fd_knhash = NULL; + } + + knhash_unlock(fdp); + + /* free the kn_hash table */ + if (kn_hash) { + FREE(kn_hash, M_KQUEUE); + } + + proc_fdlock(p); +} + +/* + * kqworkloops_dealloc - rebalance retains on kqworkloops created with + * scheduling parameters + * + * Called with proc_fdlock held. + * Returns with it locked. + * Process is in such a state that it will not try to allocate + * any more knotes during this process (stopped for exit or exec). + */ +void +kqworkloops_dealloc(proc_t p) +{ + struct filedesc *fdp = p->p_fd; + struct kqworkloop *kqwl, *kqwln; + struct kqwllist tofree; + + if (!(fdp->fd_flags & FD_WORKLOOP)) { + return; + } + + kqhash_lock(fdp); + + if (fdp->fd_kqhashmask == 0) { + kqhash_unlock(fdp); + return; + } + + LIST_INIT(&tofree); + + for (size_t i = 0; i <= fdp->fd_kqhashmask; i++) { + LIST_FOREACH_SAFE(kqwl, &fdp->fd_kqhash[i], kqwl_hashlink, kqwln) { + /* + * kqworkloops that have scheduling parameters have an + * implicit retain from kqueue_workloop_ctl that needs + * to be balanced on process exit. + */ + assert(kqwl->kqwl_params); + LIST_REMOVE(kqwl, kqwl_hashlink); + LIST_INSERT_HEAD(&tofree, kqwl, kqwl_hashlink); + } + } + + kqhash_unlock(fdp); + + LIST_FOREACH_SAFE(kqwl, &tofree, kqwl_hashlink, kqwln) { + kqworkloop_dealloc(kqwl, KQWL_DEALLOC_SKIP_HASH_REMOVE, 1); + } +} + +static int +kevent_register_validate_priority(struct kqueue *kq, struct knote *kn, + struct kevent_qos_s *kev) +{ + /* We don't care about the priority of a disabled or deleted knote */ + if (kev->flags & (EV_DISABLE | EV_DELETE)) { + return 0; + } + + if (kq->kq_state & KQ_WORKLOOP) { + /* + * Workloops need valid priorities with a QOS (excluding manager) for + * any enabled knote. + * + * When it is pre-existing, just make sure it has a valid QoS as + * kevent_register() will not use the incoming priority (filters who do + * have the responsibility to validate it again, see filt_wltouch). + * + * If the knote is being made, validate the incoming priority. + */ + if (!_pthread_priority_thread_qos(kn ? kn->kn_qos : kev->qos)) { + return ERANGE; + } + } + + return 0; +} + +/* + * Prepare a filter for waiting after register. + * + * The f_post_register_wait hook will be called later by kevent_register() + * and should call kevent_register_wait_block() + */ +static int +kevent_register_wait_prepare(struct knote *kn, struct kevent_qos_s *kev, int rc) +{ + thread_t thread = current_thread(); + + assert(knote_fops(kn)->f_extended_codes); + + if (kn->kn_thread == NULL) { + thread_reference(thread); + kn->kn_thread = thread; + } else if (kn->kn_thread != thread) { + /* + * kn_thread may be set from a previous aborted wait + * However, it has to be from the same thread. + */ + kev->flags |= EV_ERROR; + kev->data = EXDEV; + return 0; + } + + return FILTER_REGISTER_WAIT | rc; +} + +/* + * Cleanup a kevent_register_wait_prepare() effect for threads that have been + * aborted instead of properly woken up with thread_wakeup_thread(). + */ +static void +kevent_register_wait_cleanup(struct knote *kn) +{ + thread_t thread = kn->kn_thread; + kn->kn_thread = NULL; + thread_deallocate(thread); +} + +/* + * Must be called at the end of a f_post_register_wait call from a filter. + */ +static void +kevent_register_wait_block(struct turnstile *ts, thread_t thread, + thread_continue_t cont, struct _kevent_register *cont_args) +{ + turnstile_update_inheritor_complete(ts, TURNSTILE_INTERLOCK_HELD); + kqunlock(cont_args->kqwl); + cont_args->handoff_thread = thread; + thread_handoff_parameter(thread, cont, cont_args); +} + +/* + * Called by Filters using a f_post_register_wait to return from their wait. + */ +static void +kevent_register_wait_return(struct _kevent_register *cont_args) +{ + struct kqworkloop *kqwl = cont_args->kqwl; + struct kevent_qos_s *kev = &cont_args->kev; + int error = 0; + + if (cont_args->handoff_thread) { + thread_deallocate(cont_args->handoff_thread); + } + + if (kev->flags & (EV_ERROR | EV_RECEIPT)) { + if ((kev->flags & EV_ERROR) == 0) { + kev->flags |= EV_ERROR; + kev->data = 0; + } + error = kevent_modern_copyout(kev, &cont_args->ueventlist); + if (error == 0) { + cont_args->eventout++; + } + } + + kqworkloop_release(kqwl); + if (error == 0) { + *(int32_t *)¤t_uthread()->uu_rval = cont_args->eventout; + } + unix_syscall_return(error); +} + +/* + * kevent_register - add a new event to a kqueue + * + * Creates a mapping between the event source and + * the kqueue via a knote data structure. + * + * Because many/most the event sources are file + * descriptor related, the knote is linked off + * the filedescriptor table for quick access. + * + * called with nothing locked + * caller holds a reference on the kqueue + */ + +int +kevent_register(struct kqueue *kq, struct kevent_qos_s *kev, + struct knote **kn_out) +{ + struct proc *p = kq->kq_p; + const struct filterops *fops; + struct knote *kn = NULL; + int result = 0, error = 0; + unsigned short kev_flags = kev->flags; + KNOTE_LOCK_CTX(knlc); + + if (__probable(kev->filter < 0 && kev->filter + EVFILT_SYSCOUNT >= 0)) { + fops = sysfilt_ops[~kev->filter]; /* to 0-base index */ + } else { + error = EINVAL; + goto out; + } + + /* restrict EV_VANISHED to adding udata-specific dispatch kevents */ + if (__improbable((kev->flags & EV_VANISHED) && + (kev->flags & (EV_ADD | EV_DISPATCH2)) != (EV_ADD | EV_DISPATCH2))) { + error = EINVAL; + goto out; + } + + /* Simplify the flags - delete and disable overrule */ + if (kev->flags & EV_DELETE) { + kev->flags &= ~EV_ADD; + } + if (kev->flags & EV_DISABLE) { + kev->flags &= ~EV_ENABLE; + } + + if (kq->kq_state & KQ_WORKLOOP) { + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_REGISTER), + ((struct kqworkloop *)kq)->kqwl_dynamicid, + kev->udata, kev->flags, kev->filter); + } else if (kq->kq_state & KQ_WORKQ) { + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWQ_REGISTER), + 0, kev->udata, kev->flags, kev->filter); + } else { + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQ_REGISTER), + VM_KERNEL_UNSLIDE_OR_PERM(kq), + kev->udata, kev->flags, kev->filter); + } + +restart: + /* find the matching knote from the fd tables/hashes */ + kn = kq_find_knote_and_kq_lock(kq, kev, fops->f_isfd, p); + error = kevent_register_validate_priority(kq, kn, kev); + result = 0; + if (error) { + goto out; + } + + if (kn == NULL && (kev->flags & EV_ADD) == 0) { + /* + * No knote found, EV_ADD wasn't specified + */ + + if ((kev_flags & EV_ADD) && (kev_flags & EV_DELETE) && + (kq->kq_state & KQ_WORKLOOP)) { + /* + * For workloops, understand EV_ADD|EV_DELETE as a "soft" delete + * that doesn't care about ENOENT, so just pretend the deletion + * happened. + */ + } else { + error = ENOENT; + } + goto out; + } else if (kn == NULL) { + /* + * No knote found, need to attach a new one (attach) + */ + + struct fileproc *knote_fp = NULL; + + /* grab a file reference for the new knote */ + if (fops->f_isfd) { + if ((error = fp_lookup(p, kev->ident, &knote_fp, 0)) != 0) { + goto out; + } + } + + kn = knote_alloc(); + if (kn == NULL) { + error = ENOMEM; + if (knote_fp != NULL) { + fp_drop(p, kev->ident, knote_fp, 0); + } + goto out; + } + + kn->kn_fp = knote_fp; + kn->kn_is_fd = fops->f_isfd; + kn->kn_kq_packed = (intptr_t)(struct kqueue *)kq; + kn->kn_status = 0; + + /* was vanish support requested */ + if (kev->flags & EV_VANISHED) { + kev->flags &= ~EV_VANISHED; + kn->kn_status |= KN_REQVANISH; + } + + /* snapshot matching/dispatching protcol flags into knote */ + if (kev->flags & EV_DISABLE) { + kn->kn_status |= KN_DISABLED; + } + + /* + * copy the kevent state into knote + * protocol is that fflags and data + * are saved off, and cleared before + * calling the attach routine. + * + * - kn->kn_sfflags aliases with kev->xflags + * - kn->kn_sdata aliases with kev->data + * - kn->kn_filter is the top 8 bits of kev->filter + */ + kn->kn_kevent = *(struct kevent_internal_s *)kev; + kn->kn_sfflags = kev->fflags; + kn->kn_filtid = (uint8_t)~kev->filter; + kn->kn_fflags = 0; + knote_reset_priority(kq, kn, kev->qos); + + /* Add the knote for lookup thru the fd table */ + error = kq_add_knote(kq, kn, &knlc, p); + if (error) { + knote_free(kn); + if (knote_fp != NULL) { + fp_drop(p, kev->ident, knote_fp, 0); + } + + if (error == ERESTART) { + goto restart; + } + goto out; + } + + /* fp reference count now applies to knote */ + + /* + * we can't use filter_call() because f_attach can change the filter ops + * for a filter that supports f_extended_codes, so we need to reload + * knote_fops() and not use `fops`. + */ + result = fops->f_attach(kn, kev); + if (result && !knote_fops(kn)->f_extended_codes) { + result = FILTER_ACTIVE; + } + + kqlock(kq); + + if (result & FILTER_THREADREQ_NODEFEER) { + enable_preemption(); + } + + if (kn->kn_flags & EV_ERROR) { + /* + * Failed to attach correctly, so drop. + */ + kn->kn_filtid = EVFILTID_DETACHED; + error = kn->kn_sdata; + knote_drop(kq, kn, &knlc); + result = 0; + goto out; + } + + /* + * end "attaching" phase - now just attached + * + * Mark the thread request overcommit, if appropos + * + * If the attach routine indicated that an + * event is already fired, activate the knote. + */ + if ((kn->kn_qos & _PTHREAD_PRIORITY_OVERCOMMIT_FLAG) && + (kq->kq_state & KQ_WORKLOOP)) { + kqworkloop_set_overcommit((struct kqworkloop *)kq); + } + } else if (!knote_lock(kq, kn, &knlc, KNOTE_KQ_LOCK_ON_SUCCESS)) { + /* + * The knote was dropped while we were waiting for the lock, + * we need to re-evaluate entirely + */ + + goto restart; + } else if (kev->flags & EV_DELETE) { + /* + * Deletion of a knote (drop) + * + * If the filter wants to filter drop events, let it do so. + * + * defer-delete: when trying to delete a disabled EV_DISPATCH2 knote, + * we must wait for the knote to be re-enabled (unless it is being + * re-enabled atomically here). + */ + + if (knote_fops(kn)->f_allow_drop) { + bool drop; + + kqunlock(kq); + drop = knote_fops(kn)->f_allow_drop(kn, kev); + kqlock(kq); + + if (!drop) { + goto out_unlock; + } + } + + if ((kev->flags & EV_ENABLE) == 0 && + (kn->kn_flags & EV_DISPATCH2) == EV_DISPATCH2 && + (kn->kn_status & KN_DISABLED) != 0) { + kn->kn_status |= KN_DEFERDELETE; + error = EINPROGRESS; + goto out_unlock; + } + + knote_drop(kq, kn, &knlc); + goto out; + } else { + /* + * Regular update of a knote (touch) + * + * Call touch routine to notify filter of changes in filter values + * (and to re-determine if any events are fired). + * + * If the knote is in defer-delete, avoid calling the filter touch + * routine (it has delivered its last event already). + * + * If the touch routine had no failure, + * apply the requested side effects to the knote. + */ + + if (kn->kn_status & (KN_DEFERDELETE | KN_VANISHED)) { + if (kev->flags & EV_ENABLE) { + result = FILTER_ACTIVE; + } + } else { + kqunlock(kq); + result = filter_call(knote_fops(kn), f_touch(kn, kev)); + kqlock(kq); + if (result & FILTER_THREADREQ_NODEFEER) { + enable_preemption(); + } + } + + if (kev->flags & EV_ERROR) { + result = 0; + goto out_unlock; + } + + if ((kn->kn_flags & EV_UDATA_SPECIFIC) == 0 && + kn->kn_udata != kev->udata) { + // this allows klist_copy_udata() not to take locks + os_atomic_store_wide(&kn->kn_udata, kev->udata, relaxed); + } + if ((kev->flags & EV_DISABLE) && !(kn->kn_status & KN_DISABLED)) { + kn->kn_status |= KN_DISABLED; + knote_dequeue(kq, kn); + } + } + + /* accept new kevent state */ + knote_apply_touch(kq, kn, kev, result); + +out_unlock: + /* + * When the filter asked for a post-register wait, + * we leave the kqueue locked for kevent_register() + * to call the filter's f_post_register_wait hook. + */ + if (result & FILTER_REGISTER_WAIT) { + knote_unlock(kq, kn, &knlc, KNOTE_KQ_LOCK_ALWAYS); + *kn_out = kn; + } else { + knote_unlock(kq, kn, &knlc, KNOTE_KQ_UNLOCK); + } + +out: + /* output local errors through the kevent */ + if (error) { + kev->flags |= EV_ERROR; + kev->data = error; + } + return result; +} + +/* + * knote_process - process a triggered event + * + * Validate that it is really still a triggered event + * by calling the filter routines (if necessary). Hold + * a use reference on the knote to avoid it being detached. + * + * If it is still considered triggered, we will have taken + * a copy of the state under the filter lock. We use that + * snapshot to dispatch the knote for future processing (or + * not, if this was a lost event). + * + * Our caller assures us that nobody else can be processing + * events from this knote during the whole operation. But + * others can be touching or posting events to the knote + * interspersed with our processing it. + * + * caller holds a reference on the kqueue. + * kqueue locked on entry and exit - but may be dropped + */ +static int +knote_process(struct knote *kn, kevent_ctx_t kectx, + kevent_callback_t callback) +{ + struct kevent_qos_s kev; + struct kqueue *kq = knote_get_kq(kn); + KNOTE_LOCK_CTX(knlc); + int result = FILTER_ACTIVE; + int error = 0; + bool drop = false; + + /* + * Must be active or stayactive + * Must be queued and not disabled/suppressed or dropping + */ + assert(kn->kn_status & KN_QUEUED); + assert(kn->kn_status & (KN_ACTIVE | KN_STAYACTIVE)); + assert(!(kn->kn_status & (KN_DISABLED | KN_SUPPRESSED | KN_DROPPING))); + + if (kq->kq_state & KQ_WORKLOOP) { + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_PROCESS), + ((struct kqworkloop *)kq)->kqwl_dynamicid, + kn->kn_udata, kn->kn_status | (kn->kn_id << 32), + kn->kn_filtid); + } else if (kq->kq_state & KQ_WORKQ) { + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWQ_PROCESS), + 0, kn->kn_udata, kn->kn_status | (kn->kn_id << 32), + kn->kn_filtid); + } else { + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQ_PROCESS), + VM_KERNEL_UNSLIDE_OR_PERM(kq), kn->kn_udata, + kn->kn_status | (kn->kn_id << 32), kn->kn_filtid); + } + + if (!knote_lock(kq, kn, &knlc, KNOTE_KQ_LOCK_ALWAYS)) { + /* + * When the knote is dropping or has dropped, + * then there's nothing we want to process. + */ + return EJUSTRETURN; + } + + /* + * While waiting for the knote lock, we may have dropped the kq lock. + * and a touch may have disabled and dequeued the knote. + */ + if (!(kn->kn_status & KN_QUEUED)) { + knote_unlock(kq, kn, &knlc, KNOTE_KQ_LOCK_ALWAYS); + return EJUSTRETURN; + } + + /* + * For deferred-drop or vanished events, we just create a fake + * event to acknowledge end-of-life. Otherwise, we call the + * filter's process routine to snapshot the kevent state under + * the filter's locking protocol. + * + * suppress knotes to avoid returning the same event multiple times in + * a single call. + */ + knote_suppress(kq, kn); + + if (kn->kn_status & (KN_DEFERDELETE | KN_VANISHED)) { + int kev_flags = EV_DISPATCH2 | EV_ONESHOT; + if (kn->kn_status & KN_DEFERDELETE) { + kev_flags |= EV_DELETE; + } else { + kev_flags |= EV_VANISHED; + } + + /* create fake event */ + kev = (struct kevent_qos_s){ + .filter = kn->kn_filter, + .ident = kn->kn_id, + .flags = kev_flags, + .udata = kn->kn_udata, + }; + } else { + kqunlock(kq); + kev = (struct kevent_qos_s) { }; + result = filter_call(knote_fops(kn), f_process(kn, &kev)); + kqlock(kq); + } + + /* + * Determine how to dispatch the knote for future event handling. + * not-fired: just return (do not callout, leave deactivated). + * One-shot: If dispatch2, enter deferred-delete mode (unless this is + * is the deferred delete event delivery itself). Otherwise, + * drop it. + * Dispatch: don't clear state, just mark it disabled. + * Cleared: just leave it deactivated. + * Others: re-activate as there may be more events to handle. + * This will not wake up more handlers right now, but + * at the completion of handling events it may trigger + * more handler threads (TODO: optimize based on more than + * just this one event being detected by the filter). + */ + if ((result & FILTER_ACTIVE) == 0) { + if ((kn->kn_status & (KN_ACTIVE | KN_STAYACTIVE)) == 0) { + /* + * Stay active knotes should not be unsuppressed or we'd create an + * infinite loop. + * + * Some knotes (like EVFILT_WORKLOOP) can be reactivated from + * within f_process() but that doesn't necessarily make them + * ready to process, so we should leave them be. + * + * For other knotes, since we will not return an event, + * there's no point keeping the knote suppressed. + */ + knote_unsuppress(kq, kn); + } + knote_unlock(kq, kn, &knlc, KNOTE_KQ_LOCK_ALWAYS); + return EJUSTRETURN; + } + + if (result & FILTER_ADJUST_EVENT_QOS_BIT) { + knote_adjust_qos(kq, kn, result); + } + kev.qos = _pthread_priority_combine(kn->kn_qos, kn->kn_qos_override); + + if (kev.flags & EV_ONESHOT) { + if ((kn->kn_flags & EV_DISPATCH2) == EV_DISPATCH2 && + (kn->kn_status & KN_DEFERDELETE) == 0) { + /* defer dropping non-delete oneshot dispatch2 events */ + kn->kn_status |= KN_DEFERDELETE | KN_DISABLED; + } else { + drop = true; + } + } else if (kn->kn_flags & EV_DISPATCH) { + /* disable all dispatch knotes */ + kn->kn_status |= KN_DISABLED; + } else if ((kn->kn_flags & EV_CLEAR) == 0) { + /* re-activate in case there are more events */ + knote_activate(kq, kn, FILTER_ACTIVE); + } + + /* + * callback to handle each event as we find it. + * If we have to detach and drop the knote, do + * it while we have the kq unlocked. + */ + if (drop) { + knote_drop(kq, kn, &knlc); + } else { + knote_unlock(kq, kn, &knlc, KNOTE_KQ_UNLOCK); + } + + if (kev.flags & EV_VANISHED) { + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KNOTE_VANISHED), + kev.ident, kn->kn_udata, kn->kn_status | (kn->kn_id << 32), + kn->kn_filtid); + } + + error = (callback)(&kev, kectx); + kqlock(kq); + return error; +} + +/* + * Returns -1 if the kqueue was unbound and processing should not happen + */ +#define KQWQAE_BEGIN_PROCESSING 1 +#define KQWQAE_END_PROCESSING 2 +#define KQWQAE_UNBIND 3 +static int +kqworkq_acknowledge_events(struct kqworkq *kqwq, workq_threadreq_t kqr, + int kevent_flags, int kqwqae_op) +{ + thread_qos_t old_override = THREAD_QOS_UNSPECIFIED; + thread_t thread = kqr_thread_fast(kqr); + struct knote *kn; + int rc = 0; + bool unbind; + struct kqtailq *suppressq = &kqwq->kqwq_suppressed[kqr->tr_kq_qos_index]; + + kqlock_held(&kqwq->kqwq_kqueue); + + if (!TAILQ_EMPTY(suppressq)) { + /* + * Return suppressed knotes to their original state. + * For workq kqueues, suppressed ones that are still + * truly active (not just forced into the queue) will + * set flags we check below to see if anything got + * woken up. + */ + while ((kn = TAILQ_FIRST(suppressq)) != NULL) { + assert(kn->kn_status & KN_SUPPRESSED); + knote_unsuppress(kqwq, kn); + } + } + +#if DEBUG || DEVELOPMENT + thread_t self = current_thread(); + struct uthread *ut = get_bsdthread_info(self); + + assert(thread == self); + assert(ut->uu_kqr_bound == kqr); +#endif // DEBUG || DEVELOPMENT + + if (kqwqae_op == KQWQAE_UNBIND) { + unbind = true; + } else if ((kevent_flags & KEVENT_FLAG_PARKING) == 0) { + unbind = false; + } else { + unbind = !kqr->tr_kq_wakeup; + } + if (unbind) { + old_override = kqworkq_unbind_locked(kqwq, kqr, thread); + rc = -1; + /* + * request a new thread if we didn't process the whole queue or real events + * have happened (not just putting stay-active events back). + */ + if (kqr->tr_kq_wakeup) { + kqueue_threadreq_initiate(&kqwq->kqwq_kqueue, kqr, + kqr->tr_kq_qos_index, 0); + } + } + + if (rc == 0) { + /* + * Reset wakeup bit to notice events firing while we are processing, + * as we cannot rely on the bucket queue emptiness because of stay + * active knotes. + */ + kqr->tr_kq_wakeup = false; + } + + if (old_override) { + thread_drop_kevent_override(thread); + } + + return rc; +} + +/* + * Return 0 to indicate that processing should proceed, + * -1 if there is nothing to process. + * + * Called with kqueue locked and returns the same way, + * but may drop lock temporarily. + */ +static int +kqworkq_begin_processing(struct kqworkq *kqwq, workq_threadreq_t kqr, + int kevent_flags) +{ + int rc = 0; + + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWQ_PROCESS_BEGIN) | DBG_FUNC_START, + 0, kqr->tr_kq_qos_index); + + rc = kqworkq_acknowledge_events(kqwq, kqr, kevent_flags, + KQWQAE_BEGIN_PROCESSING); + + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWQ_PROCESS_BEGIN) | DBG_FUNC_END, + thread_tid(kqr_thread(kqr)), kqr->tr_kq_wakeup); + + return rc; +} + +static thread_qos_t +kqworkloop_acknowledge_events(struct kqworkloop *kqwl) +{ + kq_index_t qos = THREAD_QOS_UNSPECIFIED; + struct knote *kn, *tmp; + + kqlock_held(kqwl); + + TAILQ_FOREACH_SAFE(kn, &kqwl->kqwl_suppressed, kn_tqe, tmp) { + /* + * If a knote that can adjust QoS is disabled because of the automatic + * behavior of EV_DISPATCH, the knotes should stay suppressed so that + * further overrides keep pushing. + */ + if (knote_fops(kn)->f_adjusts_qos && (kn->kn_status & KN_DISABLED) && + (kn->kn_status & (KN_STAYACTIVE | KN_DROPPING)) == 0 && + (kn->kn_flags & (EV_DISPATCH | EV_DISABLE)) == EV_DISPATCH) { + qos = MAX(qos, kn->kn_qos_override); + continue; + } + knote_unsuppress(kqwl, kn); + } + + return qos; +} + +static int +kqworkloop_begin_processing(struct kqworkloop *kqwl, unsigned int kevent_flags) +{ + workq_threadreq_t kqr = &kqwl->kqwl_request; + struct kqueue *kq = &kqwl->kqwl_kqueue; + thread_qos_t qos_override; + thread_t thread = kqr_thread_fast(kqr); + int rc = 0, op = KQWL_UTQ_NONE; + + kqlock_held(kq); + + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_PROCESS_BEGIN) | DBG_FUNC_START, + kqwl->kqwl_dynamicid, 0, 0); + + /* nobody else should still be processing */ + assert((kq->kq_state & KQ_PROCESSING) == 0); + + kq->kq_state |= KQ_PROCESSING; + + if (!TAILQ_EMPTY(&kqwl->kqwl_suppressed)) { + op = KQWL_UTQ_RESET_WAKEUP_OVERRIDE; + } + + if (kevent_flags & KEVENT_FLAG_PARKING) { + /* + * When "parking" we want to process events and if no events are found + * unbind. + * + * However, non overcommit threads sometimes park even when they have + * more work so that the pool can narrow. For these, we need to unbind + * early, so that calling kqworkloop_update_threads_qos() can ask the + * workqueue subsystem whether the thread should park despite having + * pending events. + */ + if (kqr->tr_flags & WORKQ_TR_FLAG_OVERCOMMIT) { + op = KQWL_UTQ_PARKING; + } else { + op = KQWL_UTQ_UNBINDING; + } + } + if (op == KQWL_UTQ_NONE) { + goto done; + } + + qos_override = kqworkloop_acknowledge_events(kqwl); + + if (op == KQWL_UTQ_UNBINDING) { + kqworkloop_unbind_locked(kqwl, thread, KQWL_OVERRIDE_DROP_IMMEDIATELY); + kqworkloop_release_live(kqwl); + } + kqworkloop_update_threads_qos(kqwl, op, qos_override); + if (op == KQWL_UTQ_PARKING) { + if (!TAILQ_EMPTY(&kqwl->kqwl_queue[KQWL_BUCKET_STAYACTIVE])) { + /* + * We cannot trust tr_kq_wakeup when looking at stay active knotes. + * We need to process once, and kqworkloop_end_processing will + * handle the unbind. + */ + } else if (!kqr->tr_kq_wakeup || kqwl->kqwl_owner) { + kqworkloop_unbind_locked(kqwl, thread, KQWL_OVERRIDE_DROP_DELAYED); + kqworkloop_release_live(kqwl); + rc = -1; + } + } else if (op == KQWL_UTQ_UNBINDING) { + if (kqr_thread(kqr) == thread) { + /* + * The thread request fired again, passed the admission check and + * got bound to the current thread again. + */ + } else { + rc = -1; + } + } + + if (rc == 0) { + /* + * Reset wakeup bit to notice stay active events firing while we are + * processing, as we cannot rely on the stayactive bucket emptiness. + */ + kqwl->kqwl_wakeup_indexes &= ~KQWL_STAYACTIVE_FIRED_BIT; + } else { + kq->kq_state &= ~KQ_PROCESSING; + } + + if (rc == -1) { + kqworkloop_unbind_delayed_override_drop(thread); + } + +done: + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_PROCESS_BEGIN) | DBG_FUNC_END, + kqwl->kqwl_dynamicid, 0, 0); + + return rc; +} + +/* + * Return 0 to indicate that processing should proceed, + * -1 if there is nothing to process. + * EBADF if the kqueue is draining + * + * Called with kqueue locked and returns the same way, + * but may drop lock temporarily. + * May block. + */ +static int +kqfile_begin_processing(struct kqfile *kq) +{ + struct kqtailq *suppressq; + + kqlock_held(kq); + + assert((kq->kqf_state & (KQ_WORKQ | KQ_WORKLOOP)) == 0); + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQ_PROCESS_BEGIN) | DBG_FUNC_START, + VM_KERNEL_UNSLIDE_OR_PERM(kq), 0); + + /* wait to become the exclusive processing thread */ + for (;;) { + if (kq->kqf_state & KQ_DRAIN) { + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQ_PROCESS_BEGIN) | DBG_FUNC_END, + VM_KERNEL_UNSLIDE_OR_PERM(kq), 2); + return EBADF; + } + + if ((kq->kqf_state & KQ_PROCESSING) == 0) { + break; + } + + /* if someone else is processing the queue, wait */ + kq->kqf_state |= KQ_PROCWAIT; + suppressq = &kq->kqf_suppressed; + waitq_assert_wait64((struct waitq *)&kq->kqf_wqs, + CAST_EVENT64_T(suppressq), THREAD_UNINT | THREAD_WAIT_NOREPORT, + TIMEOUT_WAIT_FOREVER); + + kqunlock(kq); + thread_block(THREAD_CONTINUE_NULL); + kqlock(kq); + } + + /* Nobody else processing */ + + /* clear pre-posts and KQ_WAKEUP now, in case we bail early */ + waitq_set_clear_preposts(&kq->kqf_wqs); + kq->kqf_state &= ~KQ_WAKEUP; + + /* anything left to process? */ + if (TAILQ_EMPTY(&kq->kqf_queue)) { + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQ_PROCESS_BEGIN) | DBG_FUNC_END, + VM_KERNEL_UNSLIDE_OR_PERM(kq), 1); + return -1; + } + + /* convert to processing mode */ + kq->kqf_state |= KQ_PROCESSING; + + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQ_PROCESS_BEGIN) | DBG_FUNC_END, + VM_KERNEL_UNSLIDE_OR_PERM(kq)); + + return 0; +} + +/* + * Try to end the processing, only called when a workq thread is attempting to + * park (KEVENT_FLAG_PARKING is set). + * + * When returning -1, the kqworkq is setup again so that it is ready to be + * processed. + */ +static int +kqworkq_end_processing(struct kqworkq *kqwq, workq_threadreq_t kqr, + int kevent_flags) +{ + if (!TAILQ_EMPTY(&kqwq->kqwq_queue[kqr->tr_kq_qos_index])) { + /* remember we didn't process everything */ + kqr->tr_kq_wakeup = true; + } + + if (kevent_flags & KEVENT_FLAG_PARKING) { + /* + * if acknowledge events "succeeds" it means there are events, + * which is a failure condition for end_processing. + */ + int rc = kqworkq_acknowledge_events(kqwq, kqr, kevent_flags, + KQWQAE_END_PROCESSING); + if (rc == 0) { + return -1; + } + } + + return 0; +} + +/* + * Try to end the processing, only called when a workq thread is attempting to + * park (KEVENT_FLAG_PARKING is set). + * + * When returning -1, the kqworkq is setup again so that it is ready to be + * processed (as if kqworkloop_begin_processing had just been called). + * + * If successful and KEVENT_FLAG_PARKING was set in the kevent_flags, + * the kqworkloop is unbound from its servicer as a side effect. + */ +static int +kqworkloop_end_processing(struct kqworkloop *kqwl, int flags, int kevent_flags) +{ + struct kqueue *kq = &kqwl->kqwl_kqueue; + workq_threadreq_t kqr = &kqwl->kqwl_request; + thread_qos_t qos_override; + thread_t thread = kqr_thread_fast(kqr); + int rc = 0; + + kqlock_held(kq); + + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_PROCESS_END) | DBG_FUNC_START, + kqwl->kqwl_dynamicid, 0, 0); + + if (flags & KQ_PROCESSING) { + assert(kq->kq_state & KQ_PROCESSING); + + /* + * If we still have queued stayactive knotes, remember we didn't finish + * processing all of them. This should be extremely rare and would + * require to have a lot of them registered and fired. + */ + if (!TAILQ_EMPTY(&kqwl->kqwl_queue[KQWL_BUCKET_STAYACTIVE])) { + kqworkloop_update_threads_qos(kqwl, KQWL_UTQ_UPDATE_WAKEUP_QOS, + KQWL_BUCKET_STAYACTIVE); + } + + /* + * When KEVENT_FLAG_PARKING is set, we need to attempt an unbind while + * still under the lock. + * + * So we do everything kqworkloop_unbind() would do, but because we're + * inside kqueue_process(), if the workloop actually received events + * while our locks were dropped, we have the opportunity to fail the end + * processing and loop again. + * + * This avoids going through the process-wide workqueue lock hence + * scales better. + */ + if (kevent_flags & KEVENT_FLAG_PARKING) { + qos_override = kqworkloop_acknowledge_events(kqwl); + } + } + + if (kevent_flags & KEVENT_FLAG_PARKING) { + kqworkloop_update_threads_qos(kqwl, KQWL_UTQ_PARKING, qos_override); + if (kqr->tr_kq_wakeup && !kqwl->kqwl_owner) { + /* + * Reset wakeup bit to notice stay active events firing while we are + * processing, as we cannot rely on the stayactive bucket emptiness. + */ + kqwl->kqwl_wakeup_indexes &= ~KQWL_STAYACTIVE_FIRED_BIT; + rc = -1; + } else { + kqworkloop_unbind_locked(kqwl, thread, KQWL_OVERRIDE_DROP_DELAYED); + kqworkloop_release_live(kqwl); + kq->kq_state &= ~flags; + } + } else { + kq->kq_state &= ~flags; + kq->kq_state |= KQ_R2K_ARMED; + kqworkloop_update_threads_qos(kqwl, KQWL_UTQ_RECOMPUTE_WAKEUP_QOS, 0); + } + + if ((kevent_flags & KEVENT_FLAG_PARKING) && rc == 0) { + kqworkloop_unbind_delayed_override_drop(thread); + } + + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_PROCESS_END) | DBG_FUNC_END, + kqwl->kqwl_dynamicid, 0, 0); + + return rc; +} + +/* + * Called with kqueue lock held. + * + * 0: no more events + * -1: has more events + * EBADF: kqueue is in draining mode + */ +static int +kqfile_end_processing(struct kqfile *kq) +{ + struct kqtailq *suppressq = &kq->kqf_suppressed; + struct knote *kn; + int procwait; + + kqlock_held(kq); + + assert((kq->kqf_state & (KQ_WORKQ | KQ_WORKLOOP)) == 0); + + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQ_PROCESS_END), + VM_KERNEL_UNSLIDE_OR_PERM(kq), 0); + + /* + * Return suppressed knotes to their original state. + */ + while ((kn = TAILQ_FIRST(suppressq)) != NULL) { + assert(kn->kn_status & KN_SUPPRESSED); + knote_unsuppress(kq, kn); + } + + procwait = (kq->kqf_state & KQ_PROCWAIT); + kq->kqf_state &= ~(KQ_PROCESSING | KQ_PROCWAIT); + + if (procwait) { + /* first wake up any thread already waiting to process */ + waitq_wakeup64_all((struct waitq *)&kq->kqf_wqs, + CAST_EVENT64_T(suppressq), THREAD_AWAKENED, WAITQ_ALL_PRIORITIES); + } + + if (kq->kqf_state & KQ_DRAIN) { + return EBADF; + } + return (kq->kqf_state & KQ_WAKEUP) ? -1 : 0; +} + +static int +kqueue_workloop_ctl_internal(proc_t p, uintptr_t cmd, uint64_t __unused options, + struct kqueue_workloop_params *params, int *retval) +{ + int error = 0; + struct kqworkloop *kqwl; + struct filedesc *fdp = p->p_fd; + workq_threadreq_param_t trp = { }; + + switch (cmd) { + case KQ_WORKLOOP_CREATE: + if (!params->kqwlp_flags) { + error = EINVAL; + break; + } + + if ((params->kqwlp_flags & KQ_WORKLOOP_CREATE_SCHED_PRI) && + (params->kqwlp_sched_pri < 1 || + params->kqwlp_sched_pri > 63 /* MAXPRI_USER */)) { + error = EINVAL; + break; + } + + if ((params->kqwlp_flags & KQ_WORKLOOP_CREATE_SCHED_POL) && + invalid_policy(params->kqwlp_sched_pol)) { + error = EINVAL; + break; + } + + if ((params->kqwlp_flags & KQ_WORKLOOP_CREATE_CPU_PERCENT) && + (params->kqwlp_cpu_percent <= 0 || + params->kqwlp_cpu_percent > 100 || + params->kqwlp_cpu_refillms <= 0 || + params->kqwlp_cpu_refillms > 0x00ffffff)) { + error = EINVAL; + break; + } + + if (params->kqwlp_flags & KQ_WORKLOOP_CREATE_SCHED_PRI) { + trp.trp_flags |= TRP_PRIORITY; + trp.trp_pri = params->kqwlp_sched_pri; + } + if (params->kqwlp_flags & KQ_WORKLOOP_CREATE_SCHED_POL) { + trp.trp_flags |= TRP_POLICY; + trp.trp_pol = params->kqwlp_sched_pol; + } + if (params->kqwlp_flags & KQ_WORKLOOP_CREATE_CPU_PERCENT) { + trp.trp_flags |= TRP_CPUPERCENT; + trp.trp_cpupercent = (uint8_t)params->kqwlp_cpu_percent; + trp.trp_refillms = params->kqwlp_cpu_refillms; + } + + error = kqworkloop_get_or_create(p, params->kqwlp_id, &trp, + KEVENT_FLAG_DYNAMIC_KQUEUE | KEVENT_FLAG_WORKLOOP | + KEVENT_FLAG_DYNAMIC_KQ_MUST_NOT_EXIST, &kqwl); + if (error) { + break; + } + + if (!(fdp->fd_flags & FD_WORKLOOP)) { + /* FD_WORKLOOP indicates we've ever created a workloop + * via this syscall but its only ever added to a process, never + * removed. + */ + proc_fdlock(p); + fdp->fd_flags |= FD_WORKLOOP; + proc_fdunlock(p); + } + break; + case KQ_WORKLOOP_DESTROY: + error = kqworkloop_get_or_create(p, params->kqwlp_id, NULL, + KEVENT_FLAG_DYNAMIC_KQUEUE | KEVENT_FLAG_WORKLOOP | + KEVENT_FLAG_DYNAMIC_KQ_MUST_EXIST, &kqwl); + if (error) { + break; + } + kqlock(kqwl); + trp.trp_value = kqwl->kqwl_params; + if (trp.trp_flags && !(trp.trp_flags & TRP_RELEASED)) { + trp.trp_flags |= TRP_RELEASED; + kqwl->kqwl_params = trp.trp_value; + kqworkloop_release_live(kqwl); + } else { + error = EINVAL; + } + kqunlock(kqwl); + kqworkloop_release(kqwl); + break; + } + *retval = 0; + return error; +} + +int +kqueue_workloop_ctl(proc_t p, struct kqueue_workloop_ctl_args *uap, int *retval) +{ + struct kqueue_workloop_params params = { + .kqwlp_id = 0, + }; + if (uap->sz < sizeof(params.kqwlp_version)) { + return EINVAL; + } + + size_t copyin_sz = MIN(sizeof(params), uap->sz); + int rv = copyin(uap->addr, ¶ms, copyin_sz); + if (rv) { + return rv; + } + + if (params.kqwlp_version != (int)uap->sz) { + return EINVAL; + } + + return kqueue_workloop_ctl_internal(p, uap->cmd, uap->options, ¶ms, + retval); +} + +/*ARGSUSED*/ +static int +kqueue_select(struct fileproc *fp, int which, void *wq_link_id, + __unused vfs_context_t ctx) +{ + struct kqfile *kq = (struct kqfile *)fp->f_data; + struct kqtailq *suppressq = &kq->kqf_suppressed; + struct kqtailq *queue = &kq->kqf_queue; + struct knote *kn; + int retnum = 0; + + if (which != FREAD) { + return 0; + } + + kqlock(kq); + + assert((kq->kqf_state & KQ_WORKQ) == 0); + + /* + * If this is the first pass, link the wait queue associated with the + * the kqueue onto the wait queue set for the select(). Normally we + * use selrecord() for this, but it uses the wait queue within the + * selinfo structure and we need to use the main one for the kqueue to + * catch events from KN_STAYQUEUED sources. So we do the linkage manually. + * (The select() call will unlink them when it ends). + */ + if (wq_link_id != NULL) { + thread_t cur_act = current_thread(); + struct uthread * ut = get_bsdthread_info(cur_act); + + kq->kqf_state |= KQ_SEL; + waitq_link((struct waitq *)&kq->kqf_wqs, ut->uu_wqset, + WAITQ_SHOULD_LOCK, (uint64_t *)wq_link_id); + + /* always consume the reserved link object */ + waitq_link_release(*(uint64_t *)wq_link_id); + *(uint64_t *)wq_link_id = 0; + + /* + * selprocess() is expecting that we send it back the waitq + * that was just added to the thread's waitq set. In order + * to not change the selrecord() API (which is exported to + * kexts), we pass this value back through the + * void *wq_link_id pointer we were passed. We need to use + * memcpy here because the pointer may not be properly aligned + * on 32-bit systems. + */ + void *wqptr = &kq->kqf_wqs; + memcpy(wq_link_id, (void *)&wqptr, sizeof(void *)); + } + + if (kqfile_begin_processing(kq) == -1) { + kqunlock(kq); + return 0; + } + + if (!TAILQ_EMPTY(queue)) { + /* + * there is something queued - but it might be a + * KN_STAYACTIVE knote, which may or may not have + * any events pending. Otherwise, we have to walk + * the list of knotes to see, and peek at the + * (non-vanished) stay-active ones to be really sure. + */ + while ((kn = (struct knote *)TAILQ_FIRST(queue)) != NULL) { + if (kn->kn_status & KN_ACTIVE) { + retnum = 1; + goto out; + } + assert(kn->kn_status & KN_STAYACTIVE); + knote_suppress(kq, kn); + } + + /* + * There were no regular events on the queue, so take + * a deeper look at the stay-queued ones we suppressed. + */ + while ((kn = (struct knote *)TAILQ_FIRST(suppressq)) != NULL) { + KNOTE_LOCK_CTX(knlc); + int result = 0; + + /* If didn't vanish while suppressed - peek at it */ + if ((kn->kn_status & KN_DROPPING) || !knote_lock(kq, kn, &knlc, + KNOTE_KQ_LOCK_ON_FAILURE)) { + continue; + } + + result = filter_call(knote_fops(kn), f_peek(kn)); + + kqlock(kq); + knote_unlock(kq, kn, &knlc, KNOTE_KQ_LOCK_ALWAYS); + + /* unsuppress it */ + knote_unsuppress(kq, kn); + + /* has data or it has to report a vanish */ + if (result & FILTER_ACTIVE) { + retnum = 1; + goto out; + } + } + } + +out: + kqfile_end_processing(kq); + kqunlock(kq); + return retnum; +} + +/* + * kqueue_close - + */ +/*ARGSUSED*/ +static int +kqueue_close(struct fileglob *fg, __unused vfs_context_t ctx) +{ + struct kqfile *kqf = (struct kqfile *)fg->fg_data; + + assert((kqf->kqf_state & KQ_WORKQ) == 0); + kqueue_dealloc(&kqf->kqf_kqueue); + fg->fg_data = NULL; + return 0; +} + +/* + * Max depth of the nested kq path that can be created. + * Note that this has to be less than the size of kq_level + * to avoid wrapping around and mislabeling the level. + */ +#define MAX_NESTED_KQ 1000 + +/*ARGSUSED*/ +/* + * The callers has taken a use-count reference on this kqueue and will donate it + * to the kqueue we are being added to. This keeps the kqueue from closing until + * that relationship is torn down. + */ +static int +kqueue_kqfilter(struct fileproc *fp, struct knote *kn, + __unused struct kevent_qos_s *kev) +{ + struct kqfile *kqf = (struct kqfile *)fp->f_data; + struct kqueue *kq = &kqf->kqf_kqueue; + struct kqueue *parentkq = knote_get_kq(kn); + + assert((kqf->kqf_state & KQ_WORKQ) == 0); + + if (parentkq == kq || kn->kn_filter != EVFILT_READ) { + knote_set_error(kn, EINVAL); + return 0; + } + + /* + * We have to avoid creating a cycle when nesting kqueues + * inside another. Rather than trying to walk the whole + * potential DAG of nested kqueues, we just use a simple + * ceiling protocol. When a kqueue is inserted into another, + * we check that the (future) parent is not already nested + * into another kqueue at a lower level than the potenial + * child (because it could indicate a cycle). If that test + * passes, we just mark the nesting levels accordingly. + * + * Only up to MAX_NESTED_KQ can be nested. + * + * Note: kqworkq and kqworkloop cannot be nested and have reused their + * kq_level field, so ignore these as parent. + */ + + kqlock(parentkq); + + if ((parentkq->kq_state & (KQ_WORKQ | KQ_WORKLOOP)) == 0) { + if (parentkq->kq_level > 0 && + parentkq->kq_level < kq->kq_level) { + kqunlock(parentkq); + knote_set_error(kn, EINVAL); + return 0; + } + + /* set parent level appropriately */ + uint16_t plevel = (parentkq->kq_level == 0)? 2: parentkq->kq_level; + if (plevel < kq->kq_level + 1) { + if (kq->kq_level + 1 > MAX_NESTED_KQ) { + kqunlock(parentkq); + knote_set_error(kn, EINVAL); + return 0; + } + plevel = kq->kq_level + 1; + } + + parentkq->kq_level = plevel; + } + + kqunlock(parentkq); + + kn->kn_filtid = EVFILTID_KQREAD; + kqlock(kq); + KNOTE_ATTACH(&kqf->kqf_sel.si_note, kn); + /* indicate nesting in child, if needed */ + if (kq->kq_level == 0) { + kq->kq_level = 1; + } + + int count = kq->kq_count; + kqunlock(kq); + return count > 0; +} + +/* + * kqueue_drain - called when kq is closed + */ +/*ARGSUSED*/ +static int +kqueue_drain(struct fileproc *fp, __unused vfs_context_t ctx) +{ + struct kqfile *kqf = (struct kqfile *)fp->f_fglob->fg_data; + + assert((kqf->kqf_state & KQ_WORKQ) == 0); + + kqlock(kqf); + kqf->kqf_state |= KQ_DRAIN; + + /* wakeup sleeping threads */ + if ((kqf->kqf_state & (KQ_SLEEP | KQ_SEL)) != 0) { + kqf->kqf_state &= ~(KQ_SLEEP | KQ_SEL); + (void)waitq_wakeup64_all((struct waitq *)&kqf->kqf_wqs, + KQ_EVENT, + THREAD_RESTART, + WAITQ_ALL_PRIORITIES); + } + + /* wakeup threads waiting their turn to process */ + if (kqf->kqf_state & KQ_PROCWAIT) { + assert(kqf->kqf_state & KQ_PROCESSING); + + kqf->kqf_state &= ~KQ_PROCWAIT; + (void)waitq_wakeup64_all((struct waitq *)&kqf->kqf_wqs, + CAST_EVENT64_T(&kqf->kqf_suppressed), + THREAD_RESTART, WAITQ_ALL_PRIORITIES); + } + + kqunlock(kqf); + return 0; +} + +/*ARGSUSED*/ +int +kqueue_stat(struct kqueue *kq, void *ub, int isstat64, proc_t p) +{ + assert((kq->kq_state & KQ_WORKQ) == 0); + + kqlock(kq); + if (isstat64 != 0) { + struct stat64 *sb64 = (struct stat64 *)ub; + + bzero((void *)sb64, sizeof(*sb64)); + sb64->st_size = kq->kq_count; + if (kq->kq_state & KQ_KEV_QOS) { + sb64->st_blksize = sizeof(struct kevent_qos_s); + } else if (kq->kq_state & KQ_KEV64) { + sb64->st_blksize = sizeof(struct kevent64_s); + } else if (IS_64BIT_PROCESS(p)) { + sb64->st_blksize = sizeof(struct user64_kevent); + } else { + sb64->st_blksize = sizeof(struct user32_kevent); + } + sb64->st_mode = S_IFIFO; + } else { + struct stat *sb = (struct stat *)ub; + + bzero((void *)sb, sizeof(*sb)); + sb->st_size = kq->kq_count; + if (kq->kq_state & KQ_KEV_QOS) { + sb->st_blksize = sizeof(struct kevent_qos_s); + } else if (kq->kq_state & KQ_KEV64) { + sb->st_blksize = sizeof(struct kevent64_s); + } else if (IS_64BIT_PROCESS(p)) { + sb->st_blksize = sizeof(struct user64_kevent); + } else { + sb->st_blksize = sizeof(struct user32_kevent); + } + sb->st_mode = S_IFIFO; + } + kqunlock(kq); + return 0; +} + +static inline bool +kqueue_threadreq_can_use_ast(struct kqueue *kq) +{ + if (current_proc() == kq->kq_p) { + /* + * Setting an AST from a non BSD syscall is unsafe: mach_msg_trap() can + * do combined send/receive and in the case of self-IPC, the AST may bet + * set on a thread that will not return to userspace and needs the + * thread the AST would create to unblock itself. + * + * At this time, we really want to target: + * + * - kevent variants that can cause thread creations, and dispatch + * really only uses kevent_qos and kevent_id, + * + * - workq_kernreturn (directly about thread creations) + * + * - bsdthread_ctl which is used for qos changes and has direct impact + * on the creator thread scheduling decisions. + */ + switch (current_uthread()->syscall_code) { + case SYS_kevent_qos: + case SYS_kevent_id: + case SYS_workq_kernreturn: + case SYS_bsdthread_ctl: + return true; + } + } + return false; +} + +/* + * Interact with the pthread kext to request a servicing there at a specific QoS + * level. + * + * - Caller holds the workq request lock + * + * - May be called with the kqueue's wait queue set locked, + * so cannot do anything that could recurse on that. + */ +static void +kqueue_threadreq_initiate(struct kqueue *kq, workq_threadreq_t kqr, + kq_index_t qos, int flags) +{ + assert(kqr->tr_kq_wakeup); + assert(kqr_thread(kqr) == THREAD_NULL); + assert(!kqr_thread_requested(kqr)); + struct turnstile *ts = TURNSTILE_NULL; + + if (workq_is_exiting(kq->kq_p)) { + return; + } + + kqlock_held(kq); + + if (kq->kq_state & KQ_WORKLOOP) { + __assert_only struct kqworkloop *kqwl = (struct kqworkloop *)kq; + + assert(kqwl->kqwl_owner == THREAD_NULL); + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_THREQUEST), + kqwl->kqwl_dynamicid, 0, qos, kqr->tr_kq_wakeup); + ts = kqwl->kqwl_turnstile; + /* Add a thread request reference on the kqueue. */ + kqworkloop_retain(kqwl); + } else { + assert(kq->kq_state & KQ_WORKQ); + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWQ_THREQUEST), + -1, 0, qos, kqr->tr_kq_wakeup); + } + + /* + * New-style thread request supported. + * Provide the pthread kext a pointer to a workq_threadreq_s structure for + * its use until a corresponding kqueue_threadreq_bind callback. + */ + if (kqueue_threadreq_can_use_ast(kq)) { + flags |= WORKQ_THREADREQ_SET_AST_ON_FAILURE; + } + if (qos == KQWQ_QOS_MANAGER) { + qos = WORKQ_THREAD_QOS_MANAGER; + } + if (!workq_kern_threadreq_initiate(kq->kq_p, kqr, ts, qos, flags)) { + /* + * Process is shutting down or exec'ing. + * All the kqueues are going to be cleaned up + * soon. Forget we even asked for a thread - + * and make sure we don't ask for more. + */ + kq->kq_state &= ~KQ_R2K_ARMED; + kqueue_release_live(kq); + } +} + +/* + * kqueue_threadreq_bind_prepost - prepost the bind to kevent + * + * This is used when kqueue_threadreq_bind may cause a lock inversion. + */ +__attribute__((always_inline)) +void +kqueue_threadreq_bind_prepost(struct proc *p __unused, workq_threadreq_t kqr, + struct uthread *ut) +{ + ut->uu_kqr_bound = kqr; + kqr->tr_thread = ut->uu_thread; + kqr->tr_state = WORKQ_TR_STATE_BINDING; +} + +/* + * kqueue_threadreq_bind_commit - commit a bind prepost + * + * The workq code has to commit any binding prepost before the thread has + * a chance to come back to userspace (and do kevent syscalls) or be aborted. + */ +void +kqueue_threadreq_bind_commit(struct proc *p, thread_t thread) +{ + struct uthread *ut = get_bsdthread_info(thread); + workq_threadreq_t kqr = ut->uu_kqr_bound; + kqueue_t kqu = kqr_kqueue(p, kqr); + + kqlock(kqu); + if (kqr->tr_state == WORKQ_TR_STATE_BINDING) { + kqueue_threadreq_bind(p, kqr, thread, 0); + } + kqunlock(kqu); +} + +static void +kqueue_threadreq_modify(kqueue_t kqu, workq_threadreq_t kqr, kq_index_t qos, + workq_kern_threadreq_flags_t flags) +{ + assert(kqr_thread_requested_pending(kqr)); + + kqlock_held(kqu); + + if (kqueue_threadreq_can_use_ast(kqu.kq)) { + flags |= WORKQ_THREADREQ_SET_AST_ON_FAILURE; + } + workq_kern_threadreq_modify(kqu.kq->kq_p, kqr, qos, flags); +} + +/* + * kqueue_threadreq_bind - bind thread to processing kqrequest + * + * The provided thread will be responsible for delivering events + * associated with the given kqrequest. Bind it and get ready for + * the thread to eventually arrive. + */ +void +kqueue_threadreq_bind(struct proc *p, workq_threadreq_t kqr, thread_t thread, + unsigned int flags) +{ + kqueue_t kqu = kqr_kqueue(p, kqr); + struct uthread *ut = get_bsdthread_info(thread); + + kqlock_held(kqu); + + assert(ut->uu_kqueue_override == 0); + + if (kqr->tr_state == WORKQ_TR_STATE_BINDING) { + assert(ut->uu_kqr_bound == kqr); + assert(kqr->tr_thread == thread); + } else { + assert(kqr_thread_requested_pending(kqr)); + assert(kqr->tr_thread == THREAD_NULL); + assert(ut->uu_kqr_bound == NULL); + ut->uu_kqr_bound = kqr; + kqr->tr_thread = thread; + } + + kqr->tr_state = WORKQ_TR_STATE_BOUND; + + if (kqu.kq->kq_state & KQ_WORKLOOP) { + struct turnstile *ts = kqu.kqwl->kqwl_turnstile; + + if (__improbable(thread == kqu.kqwl->kqwl_owner)) { + /* + * shows that asserting here is not ok. + * + * This is not supposed to happen for correct use of the interface, + * but it is sadly possible for userspace (with the help of memory + * corruption, such as over-release of a dispatch queue) to make + * the creator thread the "owner" of a workloop. + * + * Once that happens, and that creator thread picks up the same + * workloop as a servicer, we trip this codepath. We need to fixup + * the state to forget about this thread being the owner, as the + * entire workloop state machine expects servicers to never be + * owners and everything would basically go downhill from here. + */ + kqu.kqwl->kqwl_owner = THREAD_NULL; + if (kqworkloop_override(kqu.kqwl)) { + thread_drop_kevent_override(thread); + } + } + + if (ts && (flags & KQUEUE_THREADERQ_BIND_NO_INHERITOR_UPDATE) == 0) { + /* + * Past this point, the interlock is the kq req lock again, + * so we can fix the inheritor for good. + */ + filt_wlupdate_inheritor(kqu.kqwl, ts, TURNSTILE_IMMEDIATE_UPDATE); + turnstile_update_inheritor_complete(ts, TURNSTILE_INTERLOCK_HELD); + } + + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_BIND), kqu.kqwl->kqwl_dynamicid, + thread_tid(thread), kqr->tr_kq_qos_index, + (kqr->tr_kq_override_index << 16) | kqr->tr_kq_wakeup); + + ut->uu_kqueue_override = kqr->tr_kq_override_index; + if (kqr->tr_kq_override_index) { + thread_add_servicer_override(thread, kqr->tr_kq_override_index); + } + } else { + assert(kqr->tr_kq_override_index == 0); + + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWQ_BIND), -1, + thread_tid(thread), kqr->tr_kq_qos_index, + (kqr->tr_kq_override_index << 16) | kqr->tr_kq_wakeup); + } +} + +/* + * kqueue_threadreq_cancel - abort a pending thread request + * + * Called when exiting/exec'ing. Forget our pending request. + */ +void +kqueue_threadreq_cancel(struct proc *p, workq_threadreq_t kqr) +{ + kqueue_release(kqr_kqueue(p, kqr)); +} + +workq_threadreq_param_t +kqueue_threadreq_workloop_param(workq_threadreq_t kqr) +{ + struct kqworkloop *kqwl; + workq_threadreq_param_t trp; + + assert(kqr->tr_flags & WORKQ_TR_FLAG_WORKLOOP); + kqwl = __container_of(kqr, struct kqworkloop, kqwl_request); + trp.trp_value = kqwl->kqwl_params; + return trp; +} + +/* + * kqueue_threadreq_unbind - unbind thread from processing kqueue + * + * End processing the per-QoS bucket of events and allow other threads + * to be requested for future servicing. + * + * caller holds a reference on the kqueue. + */ +void +kqueue_threadreq_unbind(struct proc *p, workq_threadreq_t kqr) +{ + if (kqr->tr_flags & WORKQ_TR_FLAG_WORKLOOP) { + kqworkloop_unbind(kqr_kqworkloop(kqr)); + } else { + kqworkq_unbind(p, kqr); + } +} + +/* + * If we aren't already busy processing events [for this QoS], + * request workq thread support as appropriate. + * + * TBD - for now, we don't segregate out processing by QoS. + * + * - May be called with the kqueue's wait queue set locked, + * so cannot do anything that could recurse on that. + */ +static void +kqworkq_wakeup(struct kqworkq *kqwq, kq_index_t qos_index) +{ + workq_threadreq_t kqr = kqworkq_get_request(kqwq, qos_index); + + /* convert to thread qos value */ + assert(qos_index < KQWQ_NBUCKETS); + + if (!kqr->tr_kq_wakeup) { + kqr->tr_kq_wakeup = true; + if (!kqr_thread_requested(kqr)) { + kqueue_threadreq_initiate(&kqwq->kqwq_kqueue, kqr, qos_index, 0); + } + } +} + +/* + * This represent the asynchronous QoS a given workloop contributes, + * hence is the max of the current active knotes (override index) + * and the workloop max qos (userspace async qos). + */ +static kq_index_t +kqworkloop_override(struct kqworkloop *kqwl) +{ + workq_threadreq_t kqr = &kqwl->kqwl_request; + return MAX(kqr->tr_kq_qos_index, kqr->tr_kq_override_index); +} + +static inline void +kqworkloop_request_fire_r2k_notification(struct kqworkloop *kqwl) +{ + workq_threadreq_t kqr = &kqwl->kqwl_request; + + kqlock_held(kqwl); + + if (kqwl->kqwl_state & KQ_R2K_ARMED) { + kqwl->kqwl_state &= ~KQ_R2K_ARMED; + act_set_astkevent(kqr_thread_fast(kqr), AST_KEVENT_RETURN_TO_KERNEL); + } +} + +static void +kqworkloop_update_threads_qos(struct kqworkloop *kqwl, int op, kq_index_t qos) +{ + workq_threadreq_t kqr = &kqwl->kqwl_request; + struct kqueue *kq = &kqwl->kqwl_kqueue; + kq_index_t old_override = kqworkloop_override(kqwl); + kq_index_t i; + + kqlock_held(kqwl); + + switch (op) { + case KQWL_UTQ_UPDATE_WAKEUP_QOS: + if (qos == KQWL_BUCKET_STAYACTIVE) { + /* + * the KQWL_BUCKET_STAYACTIVE is not a QoS bucket, we only remember + * a high watermark (kqwl_stayactive_qos) of any stay active knote + * that was ever registered with this workloop. + * + * When waitq_set__CALLING_PREPOST_HOOK__() wakes up any stay active + * knote, we use this high-watermark as a wakeup-index, and also set + * the magic KQWL_BUCKET_STAYACTIVE bit to make sure we remember + * there is at least one stay active knote fired until the next full + * processing of this bucket. + */ + kqwl->kqwl_wakeup_indexes |= KQWL_STAYACTIVE_FIRED_BIT; + qos = kqwl->kqwl_stayactive_qos; + assert(qos); + } + if (kqwl->kqwl_wakeup_indexes & (1 << qos)) { + assert(kqr->tr_kq_wakeup); + break; + } + + kqwl->kqwl_wakeup_indexes |= (1 << qos); + kqr->tr_kq_wakeup = true; + kqworkloop_request_fire_r2k_notification(kqwl); + goto recompute; + + case KQWL_UTQ_UPDATE_STAYACTIVE_QOS: + assert(qos); + if (kqwl->kqwl_stayactive_qos < qos) { + kqwl->kqwl_stayactive_qos = qos; + if (kqwl->kqwl_wakeup_indexes & KQWL_STAYACTIVE_FIRED_BIT) { + assert(kqr->tr_kq_wakeup); + kqwl->kqwl_wakeup_indexes |= (1 << qos); + goto recompute; + } + } + break; + + case KQWL_UTQ_PARKING: + case KQWL_UTQ_UNBINDING: + kqr->tr_kq_override_index = qos; + /* FALLTHROUGH */ + case KQWL_UTQ_RECOMPUTE_WAKEUP_QOS: + if (op == KQWL_UTQ_RECOMPUTE_WAKEUP_QOS) { + assert(qos == THREAD_QOS_UNSPECIFIED); + } + i = KQWL_BUCKET_STAYACTIVE; + if (TAILQ_EMPTY(&kqwl->kqwl_suppressed)) { + kqr->tr_kq_override_index = THREAD_QOS_UNSPECIFIED; + } + if (!TAILQ_EMPTY(&kqwl->kqwl_queue[i]) && + (kqwl->kqwl_wakeup_indexes & KQWL_STAYACTIVE_FIRED_BIT)) { + /* + * If the KQWL_STAYACTIVE_FIRED_BIT is set, it means a stay active + * knote may have fired, so we need to merge in kqwl_stayactive_qos. + * + * Unlike other buckets, this one is never empty but could be idle. + */ + kqwl->kqwl_wakeup_indexes &= KQWL_STAYACTIVE_FIRED_BIT; + kqwl->kqwl_wakeup_indexes |= (1 << kqwl->kqwl_stayactive_qos); + } else { + kqwl->kqwl_wakeup_indexes = 0; + } + for (i = THREAD_QOS_UNSPECIFIED + 1; i < KQWL_BUCKET_STAYACTIVE; i++) { + if (!TAILQ_EMPTY(&kqwl->kqwl_queue[i])) { + kqwl->kqwl_wakeup_indexes |= (1 << i); + } + } + if (kqwl->kqwl_wakeup_indexes) { + kqr->tr_kq_wakeup = true; + kqworkloop_request_fire_r2k_notification(kqwl); + } else { + kqr->tr_kq_wakeup = false; + } + goto recompute; + + case KQWL_UTQ_RESET_WAKEUP_OVERRIDE: + kqr->tr_kq_override_index = qos; + goto recompute; + + case KQWL_UTQ_UPDATE_WAKEUP_OVERRIDE: +recompute: + /* + * When modifying the wakeup QoS or the override QoS, we always need to + * maintain our invariant that kqr_override_index is at least as large + * as the highest QoS for which an event is fired. + * + * However this override index can be larger when there is an overriden + * suppressed knote pushing on the kqueue. + */ + if (kqwl->kqwl_wakeup_indexes > (1 << qos)) { + qos = fls(kqwl->kqwl_wakeup_indexes) - 1; /* fls is 1-based */ + } + if (kqr->tr_kq_override_index < qos) { + kqr->tr_kq_override_index = qos; + } + break; + + case KQWL_UTQ_REDRIVE_EVENTS: + break; + + case KQWL_UTQ_SET_QOS_INDEX: + kqr->tr_kq_qos_index = qos; + break; + + default: + panic("unknown kqwl thread qos update operation: %d", op); + } + + thread_t kqwl_owner = kqwl->kqwl_owner; + thread_t servicer = kqr_thread(kqr); + boolean_t qos_changed = FALSE; + kq_index_t new_override = kqworkloop_override(kqwl); + + /* + * Apply the diffs to the owner if applicable + */ + if (kqwl_owner) { +#if 0 + /* JMM - need new trace hooks for owner overrides */ + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_THADJUST), + kqwl->kqwl_dynamicid, thread_tid(kqwl_owner), kqr->tr_kq_qos_index, + (kqr->tr_kq_override_index << 16) | kqr->tr_kq_wakeup); +#endif + if (new_override == old_override) { + // nothing to do + } else if (old_override == THREAD_QOS_UNSPECIFIED) { + thread_add_kevent_override(kqwl_owner, new_override); + } else if (new_override == THREAD_QOS_UNSPECIFIED) { + thread_drop_kevent_override(kqwl_owner); + } else { /* old_override != new_override */ + thread_update_kevent_override(kqwl_owner, new_override); + } + } + + /* + * apply the diffs to the servicer + */ + if (!kqr_thread_requested(kqr)) { + /* + * No servicer, nor thread-request + * + * Make a new thread request, unless there is an owner (or the workloop + * is suspended in userland) or if there is no asynchronous work in the + * first place. + */ + + if (kqwl_owner == NULL && kqr->tr_kq_wakeup) { + int initiate_flags = 0; + if (op == KQWL_UTQ_UNBINDING) { + initiate_flags = WORKQ_THREADREQ_ATTEMPT_REBIND; + } + kqueue_threadreq_initiate(kq, kqr, new_override, initiate_flags); + } + } else if (servicer) { + /* + * Servicer in flight + * + * Just apply the diff to the servicer + */ + struct uthread *ut = get_bsdthread_info(servicer); + if (ut->uu_kqueue_override != new_override) { + if (ut->uu_kqueue_override == THREAD_QOS_UNSPECIFIED) { + thread_add_servicer_override(servicer, new_override); + } else if (new_override == THREAD_QOS_UNSPECIFIED) { + thread_drop_servicer_override(servicer); + } else { /* ut->uu_kqueue_override != new_override */ + thread_update_servicer_override(servicer, new_override); + } + ut->uu_kqueue_override = new_override; + qos_changed = TRUE; + } + } else if (new_override == THREAD_QOS_UNSPECIFIED) { + /* + * No events to deliver anymore. + * + * However canceling with turnstiles is challenging, so the fact that + * the request isn't useful will be discovered by the servicer himself + * later on. + */ + } else if (old_override != new_override) { + /* + * Request is in flight + * + * Apply the diff to the thread request + */ + kqueue_threadreq_modify(kq, kqr, new_override, WORKQ_THREADREQ_NONE); + qos_changed = TRUE; + } + + if (qos_changed) { + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_THADJUST), kqwl->kqwl_dynamicid, + thread_tid(servicer), kqr->tr_kq_qos_index, + (kqr->tr_kq_override_index << 16) | kqr->tr_kq_wakeup); + } +} + +static void +kqworkloop_wakeup(struct kqworkloop *kqwl, kq_index_t qos) +{ + if ((kqwl->kqwl_state & KQ_PROCESSING) && + kqr_thread(&kqwl->kqwl_request) == current_thread()) { + /* + * kqworkloop_end_processing() will perform the required QoS + * computations when it unsets the processing mode. + */ + return; + } + + kqworkloop_update_threads_qos(kqwl, KQWL_UTQ_UPDATE_WAKEUP_QOS, qos); +} + +static struct kqtailq * +kqueue_get_suppressed_queue(kqueue_t kq, struct knote *kn) +{ + if (kq.kq->kq_state & KQ_WORKLOOP) { + return &kq.kqwl->kqwl_suppressed; + } else if (kq.kq->kq_state & KQ_WORKQ) { + return &kq.kqwq->kqwq_suppressed[kn->kn_qos_index]; + } else { + return &kq.kqf->kqf_suppressed; + } +} + +struct turnstile * +kqueue_alloc_turnstile(kqueue_t kqu) +{ + struct kqworkloop *kqwl = kqu.kqwl; + kq_state_t kq_state; + + kq_state = os_atomic_load(&kqu.kq->kq_state, dependency); + if (kq_state & KQ_HAS_TURNSTILE) { + /* force a dependency to pair with the atomic or with release below */ + return os_atomic_load_with_dependency_on(&kqwl->kqwl_turnstile, + (uintptr_t)kq_state); + } + + if (!(kq_state & KQ_WORKLOOP)) { + return TURNSTILE_NULL; + } + + struct turnstile *ts = turnstile_alloc(), *free_ts = TURNSTILE_NULL; + bool workq_locked = false; + + kqlock(kqu); + + if (filt_wlturnstile_interlock_is_workq(kqwl)) { + workq_locked = true; + workq_kern_threadreq_lock(kqwl->kqwl_p); + } + + if (kqwl->kqwl_state & KQ_HAS_TURNSTILE) { + free_ts = ts; + ts = kqwl->kqwl_turnstile; + } else { + ts = turnstile_prepare((uintptr_t)kqwl, &kqwl->kqwl_turnstile, + ts, TURNSTILE_WORKLOOPS); + + /* release-barrier to pair with the unlocked load of kqwl_turnstile above */ + os_atomic_or(&kqwl->kqwl_state, KQ_HAS_TURNSTILE, release); + + if (filt_wlturnstile_interlock_is_workq(kqwl)) { + workq_kern_threadreq_update_inheritor(kqwl->kqwl_p, + &kqwl->kqwl_request, kqwl->kqwl_owner, + ts, TURNSTILE_IMMEDIATE_UPDATE); + /* + * The workq may no longer be the interlock after this. + * In which case the inheritor wasn't updated. + */ + } + if (!filt_wlturnstile_interlock_is_workq(kqwl)) { + filt_wlupdate_inheritor(kqwl, ts, TURNSTILE_IMMEDIATE_UPDATE); + } + } + + if (workq_locked) { + workq_kern_threadreq_unlock(kqwl->kqwl_p); + } + + kqunlock(kqu); + + if (free_ts) { + turnstile_deallocate(free_ts); + } else { + turnstile_update_inheritor_complete(ts, TURNSTILE_INTERLOCK_NOT_HELD); + } + return ts; +} + +__attribute__((always_inline)) +struct turnstile * +kqueue_turnstile(kqueue_t kqu) +{ + kq_state_t kq_state = os_atomic_load(&kqu.kq->kq_state, relaxed); + if (kq_state & KQ_WORKLOOP) { + return os_atomic_load(&kqu.kqwl->kqwl_turnstile, relaxed); + } + return TURNSTILE_NULL; +} + +__attribute__((always_inline)) +struct turnstile * +kqueue_threadreq_get_turnstile(workq_threadreq_t kqr) +{ + struct kqworkloop *kqwl = kqr_kqworkloop(kqr); + if (kqwl) { + return os_atomic_load(&kqwl->kqwl_turnstile, relaxed); + } + return TURNSTILE_NULL; +} + +static void +kqworkloop_set_overcommit(struct kqworkloop *kqwl) +{ + workq_threadreq_t kqr = &kqwl->kqwl_request; + + /* + * This test is racy, but since we never remove this bit, + * it allows us to avoid taking a lock. + */ + if (kqr->tr_flags & WORKQ_TR_FLAG_OVERCOMMIT) { + return; + } + + kqlock_held(kqwl); + + if (kqr_thread_requested_pending(kqr)) { + kqueue_threadreq_modify(kqwl, kqr, kqr->tr_qos, + WORKQ_THREADREQ_MAKE_OVERCOMMIT); + } else { + kqr->tr_flags |= WORKQ_TR_FLAG_OVERCOMMIT; + } +} + +static void +kqworkq_update_override(struct kqworkq *kqwq, struct knote *kn, + kq_index_t override_index) +{ + workq_threadreq_t kqr; + kq_index_t old_override_index; + kq_index_t queue_index = kn->kn_qos_index; + + if (override_index <= queue_index) { + return; + } + + kqr = kqworkq_get_request(kqwq, queue_index); + + kqlock_held(kqwq); + + old_override_index = kqr->tr_kq_override_index; + if (override_index > MAX(kqr->tr_kq_qos_index, old_override_index)) { + thread_t servicer = kqr_thread(kqr); + kqr->tr_kq_override_index = override_index; + + /* apply the override to [incoming?] servicing thread */ + if (servicer) { + if (old_override_index) { + thread_update_kevent_override(servicer, override_index); + } else { + thread_add_kevent_override(servicer, override_index); + } + } + } +} + +static void +kqueue_update_override(kqueue_t kqu, struct knote *kn, thread_qos_t qos) +{ + if (kqu.kq->kq_state & KQ_WORKLOOP) { + kqworkloop_update_threads_qos(kqu.kqwl, KQWL_UTQ_UPDATE_WAKEUP_OVERRIDE, + qos); + } else { + kqworkq_update_override(kqu.kqwq, kn, qos); + } +} + +static void +kqworkloop_unbind_locked(struct kqworkloop *kqwl, thread_t thread, + enum kqwl_unbind_locked_mode how) +{ + struct uthread *ut = get_bsdthread_info(thread); + workq_threadreq_t kqr = &kqwl->kqwl_request; + + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_UNBIND), kqwl->kqwl_dynamicid, + thread_tid(thread), 0, 0); + + kqlock_held(kqwl); + + assert(ut->uu_kqr_bound == kqr); + ut->uu_kqr_bound = NULL; + if (how == KQWL_OVERRIDE_DROP_IMMEDIATELY && + ut->uu_kqueue_override != THREAD_QOS_UNSPECIFIED) { + thread_drop_servicer_override(thread); + ut->uu_kqueue_override = THREAD_QOS_UNSPECIFIED; + } + + if (kqwl->kqwl_owner == NULL && kqwl->kqwl_turnstile) { + turnstile_update_inheritor(kqwl->kqwl_turnstile, + TURNSTILE_INHERITOR_NULL, TURNSTILE_IMMEDIATE_UPDATE); + turnstile_update_inheritor_complete(kqwl->kqwl_turnstile, + TURNSTILE_INTERLOCK_HELD); + } + + kqr->tr_thread = THREAD_NULL; + kqr->tr_state = WORKQ_TR_STATE_IDLE; + kqwl->kqwl_state &= ~KQ_R2K_ARMED; +} + +static void +kqworkloop_unbind_delayed_override_drop(thread_t thread) +{ + struct uthread *ut = get_bsdthread_info(thread); + assert(ut->uu_kqr_bound == NULL); + if (ut->uu_kqueue_override != THREAD_QOS_UNSPECIFIED) { + thread_drop_servicer_override(thread); + ut->uu_kqueue_override = THREAD_QOS_UNSPECIFIED; + } +} + +/* + * kqworkloop_unbind - Unbind the servicer thread of a workloop kqueue + * + * It will acknowledge events, and possibly request a new thread if: + * - there were active events left + * - we pended waitq hook callouts during processing + * - we pended wakeups while processing (or unsuppressing) + * + * Called with kqueue lock held. + */ +static void +kqworkloop_unbind(struct kqworkloop *kqwl) +{ + struct kqueue *kq = &kqwl->kqwl_kqueue; + workq_threadreq_t kqr = &kqwl->kqwl_request; + thread_t thread = kqr_thread_fast(kqr); + int op = KQWL_UTQ_PARKING; + kq_index_t qos_override = THREAD_QOS_UNSPECIFIED; + + assert(thread == current_thread()); + + kqlock(kqwl); + + /* + * Forcing the KQ_PROCESSING flag allows for QoS updates because of + * unsuppressing knotes not to be applied until the eventual call to + * kqworkloop_update_threads_qos() below. + */ + assert((kq->kq_state & KQ_PROCESSING) == 0); + if (!TAILQ_EMPTY(&kqwl->kqwl_suppressed)) { + kq->kq_state |= KQ_PROCESSING; + qos_override = kqworkloop_acknowledge_events(kqwl); + kq->kq_state &= ~KQ_PROCESSING; + } + + kqworkloop_unbind_locked(kqwl, thread, KQWL_OVERRIDE_DROP_DELAYED); + kqworkloop_update_threads_qos(kqwl, op, qos_override); + + kqunlock(kqwl); + + /* + * Drop the override on the current thread last, after the call to + * kqworkloop_update_threads_qos above. + */ + kqworkloop_unbind_delayed_override_drop(thread); + + /* If last reference, dealloc the workloop kq */ + kqworkloop_release(kqwl); +} + +static thread_qos_t +kqworkq_unbind_locked(struct kqworkq *kqwq, + workq_threadreq_t kqr, thread_t thread) +{ + struct uthread *ut = get_bsdthread_info(thread); + kq_index_t old_override = kqr->tr_kq_override_index; + + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWQ_UNBIND), -1, + thread_tid(kqr_thread(kqr)), kqr->tr_kq_qos_index, 0); + + kqlock_held(kqwq); + + assert(ut->uu_kqr_bound == kqr); + ut->uu_kqr_bound = NULL; + kqr->tr_thread = THREAD_NULL; + kqr->tr_state = WORKQ_TR_STATE_IDLE; + kqr->tr_kq_override_index = THREAD_QOS_UNSPECIFIED; + kqwq->kqwq_state &= ~KQ_R2K_ARMED; + + return old_override; +} + +/* + * kqworkq_unbind - unbind of a workq kqueue from a thread + * + * We may have to request new threads. + * This can happen there are no waiting processing threads and: + * - there were active events we never got to (count > 0) + * - we pended waitq hook callouts during processing + * - we pended wakeups while processing (or unsuppressing) + */ +static void +kqworkq_unbind(proc_t p, workq_threadreq_t kqr) +{ + struct kqworkq *kqwq = (struct kqworkq *)p->p_fd->fd_wqkqueue; + __assert_only int rc; + + kqlock(kqwq); + rc = kqworkq_acknowledge_events(kqwq, kqr, 0, KQWQAE_UNBIND); + assert(rc == -1); + kqunlock(kqwq); +} + +workq_threadreq_t +kqworkq_get_request(struct kqworkq *kqwq, kq_index_t qos_index) +{ + assert(qos_index < KQWQ_NBUCKETS); + return &kqwq->kqwq_request[qos_index]; +} + +static void +knote_reset_priority(kqueue_t kqu, struct knote *kn, pthread_priority_t pp) +{ + kq_index_t qos = _pthread_priority_thread_qos(pp); + + if (kqu.kq->kq_state & KQ_WORKLOOP) { + assert((pp & _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG) == 0); + pp = _pthread_priority_normalize(pp); + } else if (kqu.kq->kq_state & KQ_WORKQ) { + if (qos == THREAD_QOS_UNSPECIFIED) { + /* On workqueues, outside of QoS means MANAGER */ + qos = KQWQ_QOS_MANAGER; + pp = _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG; + } else { + pp = _pthread_priority_normalize(pp); + } + } else { + pp = _pthread_unspecified_priority(); + qos = THREAD_QOS_UNSPECIFIED; + } + + kn->kn_qos = pp; + + if ((kn->kn_status & KN_MERGE_QOS) == 0 || qos > kn->kn_qos_override) { + /* Never lower QoS when in "Merge" mode */ + kn->kn_qos_override = qos; + } + + /* only adjust in-use qos index when not suppressed */ + if (kn->kn_status & KN_SUPPRESSED) { + kqueue_update_override(kqu, kn, qos); + } else if (kn->kn_qos_index != qos) { + knote_dequeue(kqu, kn); + kn->kn_qos_index = qos; + } +} + +static void +knote_adjust_qos(struct kqueue *kq, struct knote *kn, int result) +{ + thread_qos_t qos_index = (result >> FILTER_ADJUST_EVENT_QOS_SHIFT) & 7; + + kqlock_held(kq); + + assert(result & FILTER_ADJUST_EVENT_QOS_BIT); + assert(qos_index < THREAD_QOS_LAST); + + /* + * Early exit for knotes that should not change QoS + */ + if (__improbable(!knote_fops(kn)->f_adjusts_qos)) { + panic("filter %d cannot change QoS", kn->kn_filtid); + } else if (__improbable(!knote_has_qos(kn))) { + return; + } + + /* + * knotes with the FALLBACK flag will only use their registration QoS if the + * incoming event has no QoS, else, the registration QoS acts as a floor. + */ + thread_qos_t req_qos = _pthread_priority_thread_qos_fast(kn->kn_qos); + if (kn->kn_qos & _PTHREAD_PRIORITY_FALLBACK_FLAG) { + if (qos_index == THREAD_QOS_UNSPECIFIED) { + qos_index = req_qos; + } + } else { + if (qos_index < req_qos) { + qos_index = req_qos; + } + } + if ((kn->kn_status & KN_MERGE_QOS) && (qos_index < kn->kn_qos_override)) { + /* Never lower QoS when in "Merge" mode */ + return; + } + + if ((kn->kn_status & KN_LOCKED) && (kn->kn_status & KN_POSTING)) { + /* + * When we're trying to update the QoS override and that both an + * f_event() and other f_* calls are running concurrently, any of these + * in flight calls may want to perform overrides that aren't properly + * serialized with each other. + * + * The first update that observes this racy situation enters a "Merge" + * mode which causes subsequent override requests to saturate the + * override instead of replacing its value. + * + * This mode is left when knote_unlock() or knote_post() + * observe that no other f_* routine is in flight. + */ + kn->kn_status |= KN_MERGE_QOS; + } + + /* + * Now apply the override if it changed. + */ + + if (kn->kn_qos_override == qos_index) { + return; + } + + kn->kn_qos_override = qos_index; + + if (kn->kn_status & KN_SUPPRESSED) { + /* + * For suppressed events, the kn_qos_index field cannot be touched as it + * allows us to know on which supress queue the knote is for a kqworkq. + * + * Also, there's no natural push applied on the kqueues when this field + * changes anyway. We hence need to apply manual overrides in this case, + * which will be cleared when the events are later acknowledged. + */ + kqueue_update_override(kq, kn, qos_index); + } else if (kn->kn_qos_index != qos_index) { + knote_dequeue(kq, kn); + kn->kn_qos_index = qos_index; + } +} + +/* + * Called back from waitq code when no threads waiting and the hook was set. + * + * Preemption is disabled - minimal work can be done in this context!!! + */ +void +waitq_set__CALLING_PREPOST_HOOK__(waitq_set_prepost_hook_t *kq_hook) +{ + kqueue_t kqu; + + kqu.kq = __container_of(kq_hook, struct kqueue, kq_waitq_hook); + assert(kqu.kq->kq_state & (KQ_WORKQ | KQ_WORKLOOP)); + + kqlock(kqu); + + if (kqu.kq->kq_count > 0) { + if (kqu.kq->kq_state & KQ_WORKLOOP) { + kqworkloop_wakeup(kqu.kqwl, KQWL_BUCKET_STAYACTIVE); + } else { + kqworkq_wakeup(kqu.kqwq, KQWQ_QOS_MANAGER); + } + } + + kqunlock(kqu); +} + +void +klist_init(struct klist *list) +{ + SLIST_INIT(list); +} + + +/* + * Query/Post each knote in the object's list + * + * The object lock protects the list. It is assumed + * that the filter/event routine for the object can + * determine that the object is already locked (via + * the hint) and not deadlock itself. + * + * The object lock should also hold off pending + * detach/drop operations. + */ +void +knote(struct klist *list, long hint) +{ + struct knote *kn; + + SLIST_FOREACH(kn, list, kn_selnext) { + knote_post(kn, hint); + } +} + +/* + * attach a knote to the specified list. Return true if this is the first entry. + * The list is protected by whatever lock the object it is associated with uses. + */ +int +knote_attach(struct klist *list, struct knote *kn) +{ + int ret = SLIST_EMPTY(list); + SLIST_INSERT_HEAD(list, kn, kn_selnext); + return ret; +} + +/* + * detach a knote from the specified list. Return true if that was the last entry. + * The list is protected by whatever lock the object it is associated with uses. + */ +int +knote_detach(struct klist *list, struct knote *kn) +{ + SLIST_REMOVE(list, kn, knote, kn_selnext); + return SLIST_EMPTY(list); +} + +/* + * knote_vanish - Indicate that the source has vanished + * + * If the knote has requested EV_VANISHED delivery, + * arrange for that. Otherwise, deliver a NOTE_REVOKE + * event for backward compatibility. + * + * The knote is marked as having vanished, but is not + * actually detached from the source in this instance. + * The actual detach is deferred until the knote drop. + * + * Our caller already has the object lock held. Calling + * the detach routine would try to take that lock + * recursively - which likely is not supported. + */ +void +knote_vanish(struct klist *list, bool make_active) +{ + struct knote *kn; + struct knote *kn_next; + + SLIST_FOREACH_SAFE(kn, list, kn_selnext, kn_next) { + struct kqueue *kq = knote_get_kq(kn); + + kqlock(kq); + if (__probable(kn->kn_status & KN_REQVANISH)) { + /* + * If EV_VANISH supported - prepare to deliver one + */ + kn->kn_status |= KN_VANISHED; + } else { + /* + * Handle the legacy way to indicate that the port/portset was + * deallocated or left the current Mach portspace (modern technique + * is with an EV_VANISHED protocol). + * + * Deliver an EV_EOF event for these changes (hopefully it will get + * delivered before the port name recycles to the same generation + * count and someone tries to re-register a kevent for it or the + * events are udata-specific - avoiding a conflict). + */ + kn->kn_flags |= EV_EOF | EV_ONESHOT; + } + if (make_active) { + knote_activate(kq, kn, FILTER_ACTIVE); + } + kqunlock(kq); + } +} + +/* + * Force a lazy allocation of the waitqset link + * of the kq_wqs associated with the kn + * if it wasn't already allocated. + * + * This allows knote_link_waitq to never block + * if reserved_link is not NULL. + */ +void +knote_link_waitqset_lazy_alloc(struct knote *kn) +{ + struct kqueue *kq = knote_get_kq(kn); + waitq_set_lazy_init_link(&kq->kq_wqs); +} + +/* + * Check if a lazy allocation for the waitqset link + * of the kq_wqs is needed. + */ +boolean_t +knote_link_waitqset_should_lazy_alloc(struct knote *kn) +{ + struct kqueue *kq = knote_get_kq(kn); + return waitq_set_should_lazy_init_link(&kq->kq_wqs); +} + +/* + * For a given knote, link a provided wait queue directly with the kqueue. + * Wakeups will happen via recursive wait queue support. But nothing will move + * the knote to the active list at wakeup (nothing calls knote()). Instead, + * we permanently enqueue them here. + * + * kqueue and knote references are held by caller. + * waitq locked by caller. + * + * caller provides the wait queue link structure and insures that the kq->kq_wqs + * is linked by previously calling knote_link_waitqset_lazy_alloc. + */ +int +knote_link_waitq(struct knote *kn, struct waitq *wq, uint64_t *reserved_link) +{ + struct kqueue *kq = knote_get_kq(kn); + kern_return_t kr; + + kr = waitq_link(wq, &kq->kq_wqs, WAITQ_ALREADY_LOCKED, reserved_link); + if (kr == KERN_SUCCESS) { + knote_markstayactive(kn); + return 0; + } else { + return EINVAL; + } +} + +/* + * Unlink the provided wait queue from the kqueue associated with a knote. + * Also remove it from the magic list of directly attached knotes. + * + * Note that the unlink may have already happened from the other side, so + * ignore any failures to unlink and just remove it from the kqueue list. + * + * On success, caller is responsible for the link structure + */ +int +knote_unlink_waitq(struct knote *kn, struct waitq *wq) +{ + struct kqueue *kq = knote_get_kq(kn); + kern_return_t kr; + + kr = waitq_unlink(wq, &kq->kq_wqs); + knote_clearstayactive(kn); + return (kr != KERN_SUCCESS) ? EINVAL : 0; +} + +/* + * remove all knotes referencing a specified fd + * + * Entered with the proc_fd lock already held. + * It returns the same way, but may drop it temporarily. + */ +void +knote_fdclose(struct proc *p, int fd) +{ + struct klist *list; + struct knote *kn; + KNOTE_LOCK_CTX(knlc); + +restart: + list = &p->p_fd->fd_knlist[fd]; + SLIST_FOREACH(kn, list, kn_link) { + struct kqueue *kq = knote_get_kq(kn); + + kqlock(kq); + + if (kq->kq_p != p) { + panic("%s: proc mismatch (kq->kq_p=%p != p=%p)", + __func__, kq->kq_p, p); + } + + /* + * If the knote supports EV_VANISHED delivery, + * transition it to vanished mode (or skip over + * it if already vanished). + */ + if (kn->kn_status & KN_VANISHED) { + kqunlock(kq); + continue; + } + + proc_fdunlock(p); + if (!knote_lock(kq, kn, &knlc, KNOTE_KQ_LOCK_ON_SUCCESS)) { + /* the knote was dropped by someone, nothing to do */ + } else if (kn->kn_status & KN_REQVANISH) { + kn->kn_status |= KN_VANISHED; + + kqunlock(kq); + knote_fops(kn)->f_detach(kn); + if (kn->kn_is_fd) { + fp_drop(p, kn->kn_id, kn->kn_fp, 0); + } + kn->kn_filtid = EVFILTID_DETACHED; + kqlock(kq); + + knote_activate(kq, kn, FILTER_ACTIVE); + knote_unlock(kq, kn, &knlc, KNOTE_KQ_UNLOCK); + } else { + knote_drop(kq, kn, &knlc); + } + + proc_fdlock(p); + goto restart; + } +} + +/* + * knote_fdfind - lookup a knote in the fd table for process + * + * If the filter is file-based, lookup based on fd index. + * Otherwise use a hash based on the ident. + * + * Matching is based on kq, filter, and ident. Optionally, + * it may also be based on the udata field in the kevent - + * allowing multiple event registration for the file object + * per kqueue. + * + * fd_knhashlock or fdlock held on entry (and exit) + */ +static struct knote * +knote_fdfind(struct kqueue *kq, + const struct kevent_internal_s *kev, + bool is_fd, + struct proc *p) +{ + struct filedesc *fdp = p->p_fd; + struct klist *list = NULL; + struct knote *kn = NULL; + + /* + * determine where to look for the knote + */ + if (is_fd) { + /* fd-based knotes are linked off the fd table */ + if (kev->kei_ident < (u_int)fdp->fd_knlistsize) { + list = &fdp->fd_knlist[kev->kei_ident]; + } + } else if (fdp->fd_knhashmask != 0) { + /* hash non-fd knotes here too */ + list = &fdp->fd_knhash[KN_HASH((u_long)kev->kei_ident, fdp->fd_knhashmask)]; + } + + /* + * scan the selected list looking for a match + */ + if (list != NULL) { + SLIST_FOREACH(kn, list, kn_link) { + if (kq == knote_get_kq(kn) && + kev->kei_ident == kn->kn_id && + kev->kei_filter == kn->kn_filter) { + if (kev->kei_flags & EV_UDATA_SPECIFIC) { + if ((kn->kn_flags & EV_UDATA_SPECIFIC) && + kev->kei_udata == kn->kn_udata) { + break; /* matching udata-specific knote */ + } + } else if ((kn->kn_flags & EV_UDATA_SPECIFIC) == 0) { + break; /* matching non-udata-specific knote */ + } + } + } + } + return kn; +} + +/* + * kq_add_knote- Add knote to the fd table for process + * while checking for duplicates. + * + * All file-based filters associate a list of knotes by file + * descriptor index. All other filters hash the knote by ident. + * + * May have to grow the table of knote lists to cover the + * file descriptor index presented. + * + * fd_knhashlock and fdlock unheld on entry (and exit). + * + * Takes a rwlock boost if inserting the knote is successful. + */ +static int +kq_add_knote(struct kqueue *kq, struct knote *kn, struct knote_lock_ctx *knlc, + struct proc *p) +{ + struct filedesc *fdp = p->p_fd; + struct klist *list = NULL; + int ret = 0; + bool is_fd = kn->kn_is_fd; + + if (is_fd) { + proc_fdlock(p); + } else { + knhash_lock(fdp); + } + + if (knote_fdfind(kq, &kn->kn_kevent, is_fd, p) != NULL) { + /* found an existing knote: we can't add this one */ + ret = ERESTART; + goto out_locked; + } + + /* knote was not found: add it now */ + if (!is_fd) { + if (fdp->fd_knhashmask == 0) { + u_long size = 0; + + list = hashinit(CONFIG_KN_HASHSIZE, M_KQUEUE, &size); + if (list == NULL) { + ret = ENOMEM; + goto out_locked; + } + + fdp->fd_knhash = list; + fdp->fd_knhashmask = size; + } + + list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)]; + SLIST_INSERT_HEAD(list, kn, kn_link); + ret = 0; + goto out_locked; + } else { + /* knote is fd based */ + + if ((u_int)fdp->fd_knlistsize <= kn->kn_id) { + u_int size = 0; + + if (kn->kn_id >= (uint64_t)p->p_rlimit[RLIMIT_NOFILE].rlim_cur + || kn->kn_id >= (uint64_t)maxfiles) { + ret = EINVAL; + goto out_locked; + } + /* have to grow the fd_knlist */ + size = fdp->fd_knlistsize; + while (size <= kn->kn_id) { + size += KQEXTENT; + } + + if (size >= (UINT_MAX / sizeof(struct klist *))) { + ret = EINVAL; + goto out_locked; + } + + MALLOC(list, struct klist *, + size * sizeof(struct klist *), M_KQUEUE, M_WAITOK); + if (list == NULL) { + ret = ENOMEM; + goto out_locked; + } + + bcopy((caddr_t)fdp->fd_knlist, (caddr_t)list, + fdp->fd_knlistsize * sizeof(struct klist *)); + bzero((caddr_t)list + + fdp->fd_knlistsize * sizeof(struct klist *), + (size - fdp->fd_knlistsize) * sizeof(struct klist *)); + FREE(fdp->fd_knlist, M_KQUEUE); + fdp->fd_knlist = list; + fdp->fd_knlistsize = size; + } + + list = &fdp->fd_knlist[kn->kn_id]; + SLIST_INSERT_HEAD(list, kn, kn_link); + ret = 0; + goto out_locked; + } + +out_locked: + if (ret == 0) { + kqlock(kq); + assert((kn->kn_status & KN_LOCKED) == 0); + (void)knote_lock(kq, kn, knlc, KNOTE_KQ_UNLOCK); + kqueue_retain(kq); /* retain a kq ref */ + } + if (is_fd) { + proc_fdunlock(p); + } else { + knhash_unlock(fdp); + } + + return ret; +} + +/* + * kq_remove_knote - remove a knote from the fd table for process + * + * If the filter is file-based, remove based on fd index. + * Otherwise remove from the hash based on the ident. + * + * fd_knhashlock and fdlock unheld on entry (and exit). + */ +static void +kq_remove_knote(struct kqueue *kq, struct knote *kn, struct proc *p, + struct knote_lock_ctx *knlc) +{ + struct filedesc *fdp = p->p_fd; + struct klist *list = NULL; + uint16_t kq_state; + bool is_fd = kn->kn_is_fd; + + if (is_fd) { + proc_fdlock(p); + } else { + knhash_lock(fdp); + } + + if (is_fd) { + assert((u_int)fdp->fd_knlistsize > kn->kn_id); + list = &fdp->fd_knlist[kn->kn_id]; + } else { + list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)]; + } + SLIST_REMOVE(list, kn, knote, kn_link); + + kqlock(kq); + kq_state = kq->kq_state; + if (knlc) { + knote_unlock_cancel(kq, kn, knlc); + } else { + kqunlock(kq); + } + if (is_fd) { + proc_fdunlock(p); + } else { + knhash_unlock(fdp); + } + + if (kq_state & KQ_DYNAMIC) { + kqworkloop_release((struct kqworkloop *)kq); + } +} + +/* + * kq_find_knote_and_kq_lock - lookup a knote in the fd table for process + * and, if the knote is found, acquires the kqlock while holding the fd table lock/spinlock. + * + * fd_knhashlock or fdlock unheld on entry (and exit) + */ + +static struct knote * +kq_find_knote_and_kq_lock(struct kqueue *kq, struct kevent_qos_s *kev, + bool is_fd, struct proc *p) +{ + struct filedesc *fdp = p->p_fd; + struct knote *kn; + + if (is_fd) { + proc_fdlock(p); + } else { + knhash_lock(fdp); + } + + /* + * Temporary horrible hack: + * this cast is gross and will go away in a future change. + * It is OK to do because we don't look at xflags/s_fflags, + * and that when we cast down the kev this way, + * the truncated filter field works. + */ + kn = knote_fdfind(kq, (struct kevent_internal_s *)kev, is_fd, p); + + if (kn) { + kqlock(kq); + assert(knote_get_kq(kn) == kq); + } + + if (is_fd) { + proc_fdunlock(p); + } else { + knhash_unlock(fdp); + } + + return kn; +} + +__attribute__((noinline)) +static void +kqfile_wakeup(struct kqfile *kqf, __unused kq_index_t qos) +{ + /* flag wakeups during processing */ + if (kqf->kqf_state & KQ_PROCESSING) { + kqf->kqf_state |= KQ_WAKEUP; + } + + /* wakeup a thread waiting on this queue */ + if (kqf->kqf_state & (KQ_SLEEP | KQ_SEL)) { + kqf->kqf_state &= ~(KQ_SLEEP | KQ_SEL); + waitq_wakeup64_all((struct waitq *)&kqf->kqf_wqs, KQ_EVENT, + THREAD_AWAKENED, WAITQ_ALL_PRIORITIES); + } + + /* wakeup other kqueues/select sets we're inside */ + KNOTE(&kqf->kqf_sel.si_note, 0); +} + +static struct kqtailq * +knote_get_tailq(kqueue_t kqu, struct knote *kn) +{ + kq_index_t qos_index = kn->kn_qos_index; + + if (kqu.kq->kq_state & KQ_WORKLOOP) { + assert(qos_index < KQWL_NBUCKETS); + } else if (kqu.kq->kq_state & KQ_WORKQ) { + assert(qos_index < KQWQ_NBUCKETS); + } else { + assert(qos_index == QOS_INDEX_KQFILE); + } + static_assert(offsetof(struct kqueue, kq_queue) == sizeof(struct kqueue), + "struct kqueue::kq_queue must be exactly at the end"); + return &kqu.kq->kq_queue[qos_index]; +} + +static void +knote_enqueue(kqueue_t kqu, struct knote *kn, kn_status_t wakeup_mask) +{ + kqlock_held(kqu); + + if ((kn->kn_status & (KN_ACTIVE | KN_STAYACTIVE)) == 0) { + return; + } + + if (kn->kn_status & (KN_DISABLED | KN_SUPPRESSED | KN_DROPPING)) { + return; + } + + if ((kn->kn_status & KN_QUEUED) == 0) { + struct kqtailq *queue = knote_get_tailq(kqu, kn); + + TAILQ_INSERT_TAIL(queue, kn, kn_tqe); + kn->kn_status |= KN_QUEUED; + kqu.kq->kq_count++; + } else if ((kn->kn_status & KN_STAYACTIVE) == 0) { + return; + } + + if (kn->kn_status & wakeup_mask) { + if (kqu.kq->kq_state & KQ_WORKLOOP) { + kqworkloop_wakeup(kqu.kqwl, kn->kn_qos_index); + } else if (kqu.kq->kq_state & KQ_WORKQ) { + kqworkq_wakeup(kqu.kqwq, kn->kn_qos_index); + } else { + kqfile_wakeup(kqu.kqf, kn->kn_qos_index); + } + } +} + +__attribute__((always_inline)) +static inline void +knote_dequeue(kqueue_t kqu, struct knote *kn) +{ + if (kn->kn_status & KN_QUEUED) { + struct kqtailq *queue = knote_get_tailq(kqu, kn); + + // attaching the knote calls knote_reset_priority() without + // the kqlock which is fine, so we can't call kqlock_held() + // if we're not queued. + kqlock_held(kqu); + + TAILQ_REMOVE(queue, kn, kn_tqe); + kn->kn_status &= ~KN_QUEUED; + kqu.kq->kq_count--; + } +} + +/* called with kqueue lock held */ +static void +knote_suppress(kqueue_t kqu, struct knote *kn) +{ + struct kqtailq *suppressq; + + kqlock_held(kqu); + + assert((kn->kn_status & KN_SUPPRESSED) == 0); + assert(kn->kn_status & KN_QUEUED); + + knote_dequeue(kqu, kn); + /* deactivate - so new activations indicate a wakeup */ + kn->kn_status &= ~KN_ACTIVE; + kn->kn_status |= KN_SUPPRESSED; + suppressq = kqueue_get_suppressed_queue(kqu, kn); + TAILQ_INSERT_TAIL(suppressq, kn, kn_tqe); +} + +__attribute__((always_inline)) +static inline void +knote_unsuppress_noqueue(kqueue_t kqu, struct knote *kn) +{ + struct kqtailq *suppressq; + + kqlock_held(kqu); + + assert(kn->kn_status & KN_SUPPRESSED); + + kn->kn_status &= ~KN_SUPPRESSED; + suppressq = kqueue_get_suppressed_queue(kqu, kn); + TAILQ_REMOVE(suppressq, kn, kn_tqe); + + /* + * If the knote is no longer active, reset its push, + * and resynchronize kn_qos_index with kn_qos_override + * for knotes with a real qos. + */ + if ((kn->kn_status & KN_ACTIVE) == 0 && knote_has_qos(kn)) { + kn->kn_qos_override = _pthread_priority_thread_qos_fast(kn->kn_qos); + } + kn->kn_qos_index = kn->kn_qos_override; +} + +/* called with kqueue lock held */ +static void +knote_unsuppress(kqueue_t kqu, struct knote *kn) +{ + if (kn->kn_status & KN_SUPPRESSED) { + knote_unsuppress_noqueue(kqu, kn); + + /* don't wakeup if unsuppressing just a stay-active knote */ + knote_enqueue(kqu, kn, KN_ACTIVE); + } +} + +__attribute__((always_inline)) +static inline void +knote_mark_active(struct knote *kn) +{ + if ((kn->kn_status & KN_ACTIVE) == 0) { + KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KNOTE_ACTIVATE), + kn->kn_udata, kn->kn_status | (kn->kn_id << 32), + kn->kn_filtid); + } + + kn->kn_status |= KN_ACTIVE; +} + +/* called with kqueue lock held */ +static void +knote_activate(kqueue_t kqu, struct knote *kn, int result) +{ + assert(result & FILTER_ACTIVE); + if (result & FILTER_ADJUST_EVENT_QOS_BIT) { + // may dequeue the knote + knote_adjust_qos(kqu.kq, kn, result); + } + knote_mark_active(kn); + knote_enqueue(kqu, kn, KN_ACTIVE | KN_STAYACTIVE); +} + +/* + * This function applies changes requested by f_attach or f_touch for + * a given filter. It proceeds in a carefully chosen order to help + * every single transition do the minimal amount of work possible. + */ +static void +knote_apply_touch(kqueue_t kqu, struct knote *kn, struct kevent_qos_s *kev, + int result) +{ + kn_status_t wakeup_mask = KN_ACTIVE; + + if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { + /* + * When a stayactive knote is reenabled, we may have missed wakeups + * while it was disabled, so we need to poll it. To do so, ask + * knote_enqueue() below to reenqueue it. + */ + wakeup_mask |= KN_STAYACTIVE; + kn->kn_status &= ~KN_DISABLED; + + /* + * it is possible for userland to have knotes registered for a given + * workloop `wl_orig` but really handled on another workloop `wl_new`. + * + * In that case, rearming will happen from the servicer thread of + * `wl_new` which if `wl_orig` is no longer being serviced, would cause + * this knote to stay suppressed forever if we only relied on + * kqworkloop_acknowledge_events to be called by `wl_orig`. + * + * However if we see the KQ_PROCESSING bit on `wl_orig` set, we can't + * unsuppress because that would mess with the processing phase of + * `wl_orig`, however it also means kqworkloop_acknowledge_events() + * will be called. + */ + if (__improbable(kn->kn_status & KN_SUPPRESSED)) { + if ((kqu.kq->kq_state & KQ_PROCESSING) == 0) { + knote_unsuppress_noqueue(kqu, kn); + } + } + } + + if ((result & FILTER_UPDATE_REQ_QOS) && kev->qos && kev->qos != kn->kn_qos) { + // may dequeue the knote + knote_reset_priority(kqu, kn, kev->qos); + } + + /* + * When we unsuppress above, or because of knote_reset_priority(), + * the knote may have been dequeued, we need to restore the invariant + * that if the knote is active it needs to be queued now that + * we're done applying changes. + */ + if (result & FILTER_ACTIVE) { + knote_activate(kqu, kn, result); + } else { + knote_enqueue(kqu, kn, wakeup_mask); + } + + if ((result & FILTER_THREADREQ_NODEFEER) && + act_clear_astkevent(current_thread(), AST_KEVENT_REDRIVE_THREADREQ)) { + workq_kern_threadreq_redrive(kqu.kq->kq_p, WORKQ_THREADREQ_NONE); + } +} + +/* + * knote_drop - disconnect and drop the knote + * + * Called with the kqueue locked, returns with the kqueue unlocked. + * + * If a knote locking context is passed, it is canceled. + * + * The knote may have already been detached from + * (or not yet attached to) its source object. + */ +static void +knote_drop(struct kqueue *kq, struct knote *kn, struct knote_lock_ctx *knlc) +{ + struct proc *p = kq->kq_p; + + kqlock_held(kq); + + assert((kn->kn_status & KN_DROPPING) == 0); + if (knlc == NULL) { + assert((kn->kn_status & KN_LOCKED) == 0); + } + kn->kn_status |= KN_DROPPING; + + if (kn->kn_status & KN_SUPPRESSED) { + knote_unsuppress_noqueue(kq, kn); + } else { + knote_dequeue(kq, kn); + } + knote_wait_for_post(kq, kn); + + knote_fops(kn)->f_detach(kn); + + /* kq may be freed when kq_remove_knote() returns */ + kq_remove_knote(kq, kn, p, knlc); + if (kn->kn_is_fd && ((kn->kn_status & KN_VANISHED) == 0)) { + fp_drop(p, kn->kn_id, kn->kn_fp, 0); + } + + knote_free(kn); +} + +void +knote_init(void) +{ + knote_zone = zinit(sizeof(struct knote), 8192 * sizeof(struct knote), + 8192, "knote zone"); + zone_change(knote_zone, Z_CACHING_ENABLED, TRUE); + + kqfile_zone = zinit(sizeof(struct kqfile), 8192 * sizeof(struct kqfile), + 8192, "kqueue file zone"); + + kqworkq_zone = zinit(sizeof(struct kqworkq), 8192 * sizeof(struct kqworkq), + 8192, "kqueue workq zone"); + + kqworkloop_zone = zinit(sizeof(struct kqworkloop), 8192 * sizeof(struct kqworkloop), + 8192, "kqueue workloop zone"); + zone_change(kqworkloop_zone, Z_CACHING_ENABLED, TRUE); + + /* allocate kq lock group attribute and group */ + kq_lck_grp_attr = lck_grp_attr_alloc_init(); + + kq_lck_grp = lck_grp_alloc_init("kqueue", kq_lck_grp_attr); + + /* Allocate kq lock attribute */ + kq_lck_attr = lck_attr_alloc_init(); + +#if CONFIG_MEMORYSTATUS + /* Initialize the memorystatus list lock */ + memorystatus_kevent_init(kq_lck_grp, kq_lck_attr); +#endif +} +SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); + +const struct filterops * +knote_fops(struct knote *kn) +{ + return sysfilt_ops[kn->kn_filtid]; +} + +static struct knote * +knote_alloc(void) +{ + struct knote *kn = ((struct knote *)zalloc(knote_zone)); + bzero(kn, sizeof(struct knote)); + return kn; +} + +static void +knote_free(struct knote *kn) +{ + assert((kn->kn_status & (KN_LOCKED | KN_POSTING)) == 0); + zfree(knote_zone, kn); +} + +#pragma mark - syscalls: kevent, kevent64, kevent_qos, kevent_id + +kevent_ctx_t +kevent_get_context(thread_t thread) +{ + uthread_t ut = get_bsdthread_info(thread); + return &ut->uu_save.uus_kevent; +} + +static inline bool +kevent_args_requesting_events(unsigned int flags, int nevents) +{ + return !(flags & KEVENT_FLAG_ERROR_EVENTS) && nevents > 0; +} + +static inline int +kevent_adjust_flags_for_proc(proc_t p, int flags) +{ + __builtin_assume(p); + return flags | (IS_64BIT_PROCESS(p) ? KEVENT_FLAG_PROC64 : 0); +} + +/*! + * @function kevent_get_kqfile + * + * @brief + * Lookup a kqfile by fd. + * + * @discussion + * Callers: kevent, kevent64, kevent_qos + * + * This is not assumed to be a fastpath (kqfile interfaces are legacy) + */ +OS_NOINLINE +static int +kevent_get_kqfile(struct proc *p, int fd, int flags, + struct fileproc **fp, struct kqueue **kqp) +{ + int error = 0; + struct kqueue *kq; + + error = fp_getfkq(p, fd, fp, &kq); + if (__improbable(error)) { + return error; + } + + uint16_t kq_state = os_atomic_load(&kq->kq_state, relaxed); + if (__improbable((kq_state & (KQ_KEV32 | KQ_KEV64 | KQ_KEV_QOS)) == 0)) { + kqlock(kq); + kq_state = kq->kq_state; + if (!(kq_state & (KQ_KEV32 | KQ_KEV64 | KQ_KEV_QOS))) { + if (flags & KEVENT_FLAG_LEGACY32) { + kq_state |= KQ_KEV32; + } else if (flags & KEVENT_FLAG_LEGACY64) { + kq_state |= KQ_KEV64; + } else { + kq_state |= KQ_KEV_QOS; + } + kq->kq_state = kq_state; + } + kqunlock(kq); + } + + /* + * kqfiles can't be used through the legacy kevent() + * and other interfaces at the same time. + */ + if (__improbable((bool)(flags & KEVENT_FLAG_LEGACY32) != + (bool)(kq_state & KQ_KEV32))) { + fp_drop(p, fd, *fp, 0); + return EINVAL; + } + + *kqp = kq; + return 0; +} + +/*! + * @function kevent_get_kqwq + * + * @brief + * Lookup or create the process kqwq (faspath). + * + * @discussion + * Callers: kevent64, kevent_qos + */ +OS_ALWAYS_INLINE +static int +kevent_get_kqwq(proc_t p, int flags, int nevents, struct kqueue **kqp) +{ + struct kqworkq *kqwq = p->p_fd->fd_wqkqueue; + + if (__improbable(kevent_args_requesting_events(flags, nevents))) { + return EINVAL; + } + if (__improbable(kqwq == NULL)) { + kqwq = kqworkq_alloc(p, flags); + if (__improbable(kqwq == NULL)) { + return ENOMEM; + } + } + + *kqp = &kqwq->kqwq_kqueue; + return 0; +} + +#pragma mark kevent copyio + +/*! + * @function kevent_get_data_size + * + * @brief + * Copies in the extra data size from user-space. + */ +static int +kevent_get_data_size(int flags, user_addr_t data_avail, user_addr_t data_out, + kevent_ctx_t kectx) +{ + if (!data_avail || !data_out) { + kectx->kec_data_size = 0; + kectx->kec_data_resid = 0; + } else if (flags & KEVENT_FLAG_PROC64) { + user64_size_t usize = 0; + int error = copyin((user_addr_t)data_avail, &usize, sizeof(usize)); + if (__improbable(error)) { + return error; + } + kectx->kec_data_resid = kectx->kec_data_size = (user_size_t)usize; + } else { + user32_size_t usize = 0; + int error = copyin((user_addr_t)data_avail, &usize, sizeof(usize)); + if (__improbable(error)) { + return error; + } + kectx->kec_data_avail = data_avail; + kectx->kec_data_resid = kectx->kec_data_size = (user_size_t)usize; + } + kectx->kec_data_out = data_out; + kectx->kec_data_avail = data_avail; + return 0; +} + +/*! + * @function kevent_put_data_size + * + * @brief + * Copies out the residual data size to user-space if any has been used. + */ +static int +kevent_put_data_size(unsigned int flags, kevent_ctx_t kectx) +{ + if (kectx->kec_data_resid == kectx->kec_data_size) { + return 0; + } + if (flags & KEVENT_FLAG_KERNEL) { + *(user_size_t *)(uintptr_t)kectx->kec_data_avail = kectx->kec_data_resid; + return 0; + } + if (flags & KEVENT_FLAG_PROC64) { + user64_size_t usize = (user64_size_t)kectx->kec_data_resid; + return copyout(&usize, (user_addr_t)kectx->kec_data_avail, sizeof(usize)); + } else { + user32_size_t usize = (user32_size_t)kectx->kec_data_resid; + return copyout(&usize, (user_addr_t)kectx->kec_data_avail, sizeof(usize)); + } +} + +/*! + * @function kevent_legacy_copyin + * + * @brief + * Handles the copyin of a kevent/kevent64 event. + */ +static int +kevent_legacy_copyin(user_addr_t *addrp, struct kevent_qos_s *kevp, unsigned int flags) +{ + int error; + + assert((flags & (KEVENT_FLAG_LEGACY32 | KEVENT_FLAG_LEGACY64)) != 0); + + if (flags & KEVENT_FLAG_LEGACY64) { + struct kevent64_s kev64; + + error = copyin(*addrp, (caddr_t)&kev64, sizeof(kev64)); + if (__improbable(error)) { + return error; + } + *addrp += sizeof(kev64); + *kevp = (struct kevent_qos_s){ + .ident = kev64.ident, + .filter = kev64.filter, + /* Make sure user doesn't pass in any system flags */ + .flags = kev64.flags & ~EV_SYSFLAGS, + .udata = kev64.udata, + .fflags = kev64.fflags, + .data = kev64.data, + .ext[0] = kev64.ext[0], + .ext[1] = kev64.ext[1], + }; + } else if (flags & KEVENT_FLAG_PROC64) { + struct user64_kevent kev64; + + error = copyin(*addrp, (caddr_t)&kev64, sizeof(kev64)); + if (__improbable(error)) { + return error; + } + *addrp += sizeof(kev64); + *kevp = (struct kevent_qos_s){ + .ident = kev64.ident, + .filter = kev64.filter, + /* Make sure user doesn't pass in any system flags */ + .flags = kev64.flags & ~EV_SYSFLAGS, + .udata = kev64.udata, + .fflags = kev64.fflags, + .data = kev64.data, + }; + } else { + struct user32_kevent kev32; + + error = copyin(*addrp, (caddr_t)&kev32, sizeof(kev32)); + if (__improbable(error)) { + return error; + } + *addrp += sizeof(kev32); + *kevp = (struct kevent_qos_s){ + .ident = (uintptr_t)kev32.ident, + .filter = kev32.filter, + /* Make sure user doesn't pass in any system flags */ + .flags = kev32.flags & ~EV_SYSFLAGS, + .udata = CAST_USER_ADDR_T(kev32.udata), + .fflags = kev32.fflags, + .data = (intptr_t)kev32.data, + }; + } + + return 0; +} + +/*! + * @function kevent_modern_copyin + * + * @brief + * Handles the copyin of a kevent_qos/kevent_id event. + */ +static int +kevent_modern_copyin(user_addr_t *addrp, struct kevent_qos_s *kevp) +{ + int error = copyin(*addrp, (caddr_t)kevp, sizeof(struct kevent_qos_s)); + if (__probable(!error)) { + /* Make sure user doesn't pass in any system flags */ + *addrp += sizeof(struct kevent_qos_s); + kevp->flags &= ~EV_SYSFLAGS; + } + return error; +} + +/*! + * @function kevent_legacy_copyout + * + * @brief + * Handles the copyout of a kevent/kevent64 event. + */ +static int +kevent_legacy_copyout(struct kevent_qos_s *kevp, user_addr_t *addrp, unsigned int flags) +{ + int advance; + int error; + + assert((flags & (KEVENT_FLAG_LEGACY32 | KEVENT_FLAG_LEGACY64)) != 0); + + /* + * fully initialize the differnt output event structure + * types from the internal kevent (and some universal + * defaults for fields not represented in the internal + * form). + * + * Note: these structures have no padding hence the C99 + * initializers below do not leak kernel info. + */ + if (flags & KEVENT_FLAG_LEGACY64) { + struct kevent64_s kev64 = { + .ident = kevp->ident, + .filter = kevp->filter, + .flags = kevp->flags, + .fflags = kevp->fflags, + .data = (int64_t)kevp->data, + .udata = kevp->udata, + .ext[0] = kevp->ext[0], + .ext[1] = kevp->ext[1], + }; + advance = sizeof(struct kevent64_s); + error = copyout((caddr_t)&kev64, *addrp, advance); + } else if (flags & KEVENT_FLAG_PROC64) { + /* + * deal with the special case of a user-supplied + * value of (uintptr_t)-1. + */ + uint64_t ident = (kevp->ident == (uintptr_t)-1) ? + (uint64_t)-1LL : (uint64_t)kevp->ident; + struct user64_kevent kev64 = { + .ident = ident, + .filter = kevp->filter, + .flags = kevp->flags, + .fflags = kevp->fflags, + .data = (int64_t) kevp->data, + .udata = kevp->udata, + }; + advance = sizeof(kev64); + error = copyout((caddr_t)&kev64, *addrp, advance); + } else { + struct user32_kevent kev32 = { + .ident = (uint32_t)kevp->ident, + .filter = kevp->filter, + .flags = kevp->flags, + .fflags = kevp->fflags, + .data = (int32_t)kevp->data, + .udata = kevp->udata, + }; + advance = sizeof(kev32); + error = copyout((caddr_t)&kev32, *addrp, advance); + } + if (__probable(!error)) { + *addrp += advance; + } + return error; +} + +/*! + * @function kevent_modern_copyout + * + * @brief + * Handles the copyout of a kevent_qos/kevent_id event. + */ +OS_ALWAYS_INLINE +static inline int +kevent_modern_copyout(struct kevent_qos_s *kevp, user_addr_t *addrp) +{ + int error = copyout((caddr_t)kevp, *addrp, sizeof(struct kevent_qos_s)); + if (__probable(!error)) { + *addrp += sizeof(struct kevent_qos_s); + } + return error; +} + +#pragma mark kevent core implementation + +/*! + * @function kevent_callback_inline + * + * @brief + * Callback for each individual event + * + * @discussion + * This is meant to be inlined in kevent_modern_callback and + * kevent_legacy_callback. + */ +OS_ALWAYS_INLINE +static inline int +kevent_callback_inline(struct kevent_qos_s *kevp, kevent_ctx_t kectx, bool legacy) +{ + int error; + + assert(kectx->kec_process_noutputs < kectx->kec_process_nevents); + + /* + * Copy out the appropriate amount of event data for this user. + */ + if (legacy) { + error = kevent_legacy_copyout(kevp, &kectx->kec_process_eventlist, + kectx->kec_process_flags); + } else { + error = kevent_modern_copyout(kevp, &kectx->kec_process_eventlist); + } + + /* + * If there isn't space for additional events, return + * a harmless error to stop the processing here + */ + if (error == 0 && ++kectx->kec_process_noutputs == kectx->kec_process_nevents) { + error = EWOULDBLOCK; + } + return error; +} + +/*! + * @function kevent_modern_callback + * + * @brief + * Callback for each individual modern event. + * + * @discussion + * This callback handles kevent_qos/kevent_id events. + */ +static int +kevent_modern_callback(struct kevent_qos_s *kevp, kevent_ctx_t kectx) +{ + return kevent_callback_inline(kevp, kectx, /*legacy*/ false); +} + +/*! + * @function kevent_legacy_callback + * + * @brief + * Callback for each individual legacy event. + * + * @discussion + * This callback handles kevent/kevent64 events. + */ +static int +kevent_legacy_callback(struct kevent_qos_s *kevp, kevent_ctx_t kectx) +{ + return kevent_callback_inline(kevp, kectx, /*legacy*/ true); +} + +/*! + * @function kevent_cleanup + * + * @brief + * Handles the cleanup returning from a kevent call. + * + * @discussion + * kevent entry points will take a reference on workloops, + * and a usecount on the fileglob of kqfiles. + * + * This function undoes this on the exit paths of kevents. + * + * @returns + * The error to return to userspace. + */ +static int +kevent_cleanup(kqueue_t kqu, int flags, int error, kevent_ctx_t kectx) +{ + // poll should not call any codepath leading to this + assert((flags & KEVENT_FLAG_POLL) == 0); + + if (flags & KEVENT_FLAG_WORKLOOP) { + kqworkloop_release(kqu.kqwl); + } else if (flags & KEVENT_FLAG_WORKQ) { + /* nothing held */ + } else { + fp_drop(kqu.kqf->kqf_p, kectx->kec_fd, kectx->kec_fp, 0); + } + + /* don't restart after signals... */ + if (error == ERESTART) { + error = EINTR; + } else if (error == 0) { + /* don't abandon other output just because of residual copyout failures */ + (void)kevent_put_data_size(flags, kectx); + } + + if (flags & KEVENT_FLAG_PARKING) { + thread_t th = current_thread(); + struct uthread *uth = get_bsdthread_info(th); + if (uth->uu_kqr_bound) { + thread_unfreeze_base_pri(th); + } + } + return error; +} + +/*! + * @function kqueue_process + * + * @brief + * Process the triggered events in a kqueue. + * + * @discussion + * Walk the queued knotes and validate that they are really still triggered + * events by calling the filter routines (if necessary). + * + * For each event that is still considered triggered, invoke the callback + * routine provided. + * + * caller holds a reference on the kqueue. + * kqueue locked on entry and exit - but may be dropped + * kqueue list locked (held for duration of call) + * + * This is only called by kqueue_scan() so that the compiler can inline it. + * + * @returns + * - 0: no event was returned, no other error occured + * - EBADF: the kqueue is being destroyed (KQ_DRAIN is set) + * - EWOULDBLOCK: (not an error) events have been found and we should return + * - EFAULT: copyout failed + * - filter specific errors + */ +static int +kqueue_process(kqueue_t kqu, int flags, kevent_ctx_t kectx, + kevent_callback_t callback) +{ + workq_threadreq_t kqr = current_uthread()->uu_kqr_bound; + struct knote *kn; + int error = 0, rc = 0; + struct kqtailq *base_queue, *queue; +#if DEBUG || DEVELOPMENT + int retries = 64; +#endif + uint16_t kq_type = (kqu.kq->kq_state & (KQ_WORKQ | KQ_WORKLOOP)); + + if (kq_type & KQ_WORKQ) { + rc = kqworkq_begin_processing(kqu.kqwq, kqr, flags); + } else if (kq_type & KQ_WORKLOOP) { + rc = kqworkloop_begin_processing(kqu.kqwl, flags); + } else { +kqfile_retry: + rc = kqfile_begin_processing(kqu.kqf); + if (rc == EBADF) { + return EBADF; + } + } + + if (rc == -1) { + /* Nothing to process */ + return 0; + } + + /* + * loop through the enqueued knotes associated with this request, + * processing each one. Each request may have several queues + * of knotes to process (depending on the type of kqueue) so we + * have to loop through all the queues as long as we have additional + * space. + */ + +process_again: + if (kq_type & KQ_WORKQ) { + base_queue = queue = &kqu.kqwq->kqwq_queue[kqr->tr_kq_qos_index]; + } else if (kq_type & KQ_WORKLOOP) { + base_queue = &kqu.kqwl->kqwl_queue[0]; + queue = &kqu.kqwl->kqwl_queue[KQWL_NBUCKETS - 1]; + } else { + base_queue = queue = &kqu.kqf->kqf_queue; + } + + do { + while ((kn = TAILQ_FIRST(queue)) != NULL) { + error = knote_process(kn, kectx, callback); + if (error == EJUSTRETURN) { + error = 0; + } else if (__improbable(error)) { + /* error is EWOULDBLOCK when the out event array is full */ + goto stop_processing; + } + } + } while (queue-- > base_queue); + + if (kectx->kec_process_noutputs) { + /* callers will transform this into no error */ + error = EWOULDBLOCK; + } + +stop_processing: + /* + * If KEVENT_FLAG_PARKING is set, and no kevents have been returned, + * we want to unbind the kqrequest from the thread. + * + * However, because the kq locks are dropped several times during process, + * new knotes may have fired again, in which case, we want to fail the end + * processing and process again, until it converges. + * + * If we have an error or returned events, end processing never fails. + */ + if (error) { + flags &= ~KEVENT_FLAG_PARKING; + } + if (kq_type & KQ_WORKQ) { + rc = kqworkq_end_processing(kqu.kqwq, kqr, flags); + } else if (kq_type & KQ_WORKLOOP) { + rc = kqworkloop_end_processing(kqu.kqwl, KQ_PROCESSING, flags); + } else { + rc = kqfile_end_processing(kqu.kqf); + } + + if (__probable(error)) { + return error; + } + + if (__probable(rc >= 0)) { + assert(rc == 0 || rc == EBADF); + return rc; + } + +#if DEBUG || DEVELOPMENT + if (retries-- == 0) { + panic("kevent: way too many knote_process retries, kq: %p (0x%04x)", + kqu.kq, kqu.kq->kq_state); + } +#endif + if (kq_type & (KQ_WORKQ | KQ_WORKLOOP)) { + assert(flags & KEVENT_FLAG_PARKING); + goto process_again; + } else { + goto kqfile_retry; + } +} + +/*! + * @function kqueue_scan_continue + * + * @brief + * The continuation used by kqueue_scan for kevent entry points. + * + * @discussion + * Assumes we inherit a use/ref count on the kq or its fileglob. + * + * This is called by kqueue_scan if neither KEVENT_FLAG_POLL nor + * KEVENT_FLAG_KERNEL was set, and the caller had to wait. + */ +OS_NORETURN OS_NOINLINE +static void +kqueue_scan_continue(void *data, wait_result_t wait_result) +{ + uthread_t ut = current_uthread(); + kevent_ctx_t kectx = &ut->uu_save.uus_kevent; + int error = 0, flags = kectx->kec_process_flags; + struct kqueue *kq = data; + + /* + * only kevent variants call in here, so we know the callback is + * kevent_legacy_callback or kevent_modern_callback. + */ + assert((flags & (KEVENT_FLAG_POLL | KEVENT_FLAG_KERNEL)) == 0); + + switch (wait_result) { + case THREAD_AWAKENED: + if (__improbable(flags & (KEVENT_FLAG_LEGACY32 | KEVENT_FLAG_LEGACY64))) { + error = kqueue_scan(kq, flags, kectx, kevent_legacy_callback); + } else { + error = kqueue_scan(kq, flags, kectx, kevent_modern_callback); + } + break; + case THREAD_TIMED_OUT: + error = 0; + break; + case THREAD_INTERRUPTED: + error = EINTR; + break; + case THREAD_RESTART: + error = EBADF; + break; + default: + panic("%s: - invalid wait_result (%d)", __func__, wait_result); + } + + + error = kevent_cleanup(kq, flags, error, kectx); + *(int32_t *)&ut->uu_rval = kectx->kec_process_noutputs; + unix_syscall_return(error); +} + +/*! + * @function kqueue_scan + * + * @brief + * Scan and wait for events in a kqueue (used by poll & kevent). + * + * @discussion + * Process the triggered events in a kqueue. + * + * If there are no events triggered arrange to wait for them: + * - unless KEVENT_FLAG_IMMEDIATE is set in kectx->kec_process_flags + * - possibly until kectx->kec_deadline expires + * + * When it waits, and that neither KEVENT_FLAG_POLL nor KEVENT_FLAG_KERNEL + * are set, then it will wait in the kqueue_scan_continue continuation. + * + * poll() will block in place, and KEVENT_FLAG_KERNEL calls + * all pass KEVENT_FLAG_IMMEDIATE and will not wait. + * + * @param kq + * The kqueue being scanned. + * + * @param flags + * The KEVENT_FLAG_* flags for this call. + * + * @param kectx + * The context used for this scan. + * The uthread_t::uu_save.uus_kevent storage is used for this purpose. + * + * @param callback + * The callback to be called on events sucessfully processed. + * (Either kevent_legacy_callback, kevent_modern_callback or poll_callback) + */ +int +kqueue_scan(struct kqueue *kq, int flags, kevent_ctx_t kectx, + kevent_callback_t callback) +{ + int error; + + for (;;) { + kqlock(kq); + error = kqueue_process(kq, flags, kectx, callback); + + /* + * If we got an error, events returned (EWOULDBLOCK) + * or blocking was disallowed (KEVENT_FLAG_IMMEDIATE), + * just return. + */ + if (__probable(error || (flags & KEVENT_FLAG_IMMEDIATE))) { + kqunlock(kq); + return error == EWOULDBLOCK ? 0 : error; + } + + waitq_assert_wait64_leeway((struct waitq *)&kq->kq_wqs, + KQ_EVENT, THREAD_ABORTSAFE, TIMEOUT_URGENCY_USER_NORMAL, + kectx->kec_deadline, TIMEOUT_NO_LEEWAY); + kq->kq_state |= KQ_SLEEP; + + kqunlock(kq); + + if (__probable((flags & (KEVENT_FLAG_POLL | KEVENT_FLAG_KERNEL)) == 0)) { + thread_block_parameter(kqueue_scan_continue, kq); + __builtin_unreachable(); + } + + wait_result_t wr = thread_block(THREAD_CONTINUE_NULL); + switch (wr) { + case THREAD_AWAKENED: + break; + case THREAD_TIMED_OUT: + return 0; + case THREAD_INTERRUPTED: + return EINTR; + case THREAD_RESTART: + return EBADF; + default: + panic("%s: - bad wait_result (%d)", __func__, wr); + } + } +} + +/*! + * @function kevent_internal + * + * @brief + * Common kevent code. + * + * @discussion + * Needs to be inlined to specialize for legacy or modern and + * eliminate dead code. + * + * This is the core logic of kevent entry points, that will: + * - register kevents + * - optionally scan the kqueue for events + * + * The caller is giving kevent_internal a reference on the kqueue + * or its fileproc that needs to be cleaned up by kevent_cleanup(). + */ +OS_ALWAYS_INLINE +static inline int +kevent_internal(kqueue_t kqu, + user_addr_t changelist, int nchanges, + user_addr_t ueventlist, int nevents, + int flags, kevent_ctx_t kectx, int32_t *retval, + bool legacy) +{ + int error = 0, noutputs = 0, register_rc; + + /* only bound threads can receive events on workloops */ + if (!legacy && (flags & KEVENT_FLAG_WORKLOOP)) { +#if CONFIG_WORKLOOP_DEBUG + UU_KEVENT_HISTORY_WRITE_ENTRY(current_uthread(), { + .uu_kqid = kqu.kqwl->kqwl_dynamicid, + .uu_kq = error ? NULL : kqu.kq, + .uu_error = error, + .uu_nchanges = nchanges, + .uu_nevents = nevents, + .uu_flags = flags, + }); +#endif // CONFIG_WORKLOOP_DEBUG + + if (flags & KEVENT_FLAG_KERNEL) { + /* see kevent_workq_internal */ + error = copyout(&kqu.kqwl->kqwl_dynamicid, + ueventlist - sizeof(kqueue_id_t), sizeof(kqueue_id_t)); + kectx->kec_data_resid -= sizeof(kqueue_id_t); + if (__improbable(error)) { + goto out; + } + } + + if (kevent_args_requesting_events(flags, nevents)) { + /* + * Disable the R2K notification while doing a register, if the + * caller wants events too, we don't want the AST to be set if we + * will process these events soon. + */ + kqlock(kqu); + kqu.kq->kq_state &= ~KQ_R2K_ARMED; + kqunlock(kqu); + flags |= KEVENT_FLAG_NEEDS_END_PROCESSING; + } + } + + /* register all the change requests the user provided... */ + while (nchanges > 0 && error == 0) { + struct kevent_qos_s kev; + struct knote *kn = NULL; + + if (legacy) { + error = kevent_legacy_copyin(&changelist, &kev, flags); + } else { + error = kevent_modern_copyin(&changelist, &kev); + } + if (error) { + break; + } + + register_rc = kevent_register(kqu.kq, &kev, &kn); + if (__improbable(!legacy && (register_rc & FILTER_REGISTER_WAIT))) { + thread_t thread = current_thread(); + + kqlock_held(kqu); + + if (act_clear_astkevent(thread, AST_KEVENT_REDRIVE_THREADREQ)) { + workq_kern_threadreq_redrive(kqu.kq->kq_p, WORKQ_THREADREQ_NONE); + } + + // f_post_register_wait is meant to call a continuation and not to + // return, which is why we don't support FILTER_REGISTER_WAIT if + // KEVENT_FLAG_ERROR_EVENTS is not passed, or if the event that + // waits isn't the last. + // + // It is implementable, but not used by any userspace code at the + // moment, so for now return ENOTSUP if someone tries to do it. + if (nchanges == 1 && noutputs < nevents && + (flags & KEVENT_FLAG_KERNEL) == 0 && + (flags & KEVENT_FLAG_PARKING) == 0 && + (flags & KEVENT_FLAG_ERROR_EVENTS) && + (flags & KEVENT_FLAG_WORKLOOP)) { + uthread_t ut = get_bsdthread_info(thread); + + /* + * store the continuation/completion data in the uthread + * + * Note: the kectx aliases with this, + * and is destroyed in the process. + */ + ut->uu_save.uus_kevent_register = (struct _kevent_register){ + .kev = kev, + .kqwl = kqu.kqwl, + .eventout = noutputs, + .ueventlist = ueventlist, + }; + knote_fops(kn)->f_post_register_wait(ut, kn, + &ut->uu_save.uus_kevent_register); + __builtin_unreachable(); + } + kqunlock(kqu); + + kev.flags |= EV_ERROR; + kev.data = ENOTSUP; + } else { + assert((register_rc & FILTER_REGISTER_WAIT) == 0); + } + + // keep in sync with kevent_register_wait_return() + if (noutputs < nevents && (kev.flags & (EV_ERROR | EV_RECEIPT))) { + if ((kev.flags & EV_ERROR) == 0) { + kev.flags |= EV_ERROR; + kev.data = 0; + } + if (legacy) { + error = kevent_legacy_copyout(&kev, &ueventlist, flags); + } else { + error = kevent_modern_copyout(&kev, &ueventlist); + } + if (error == 0) { + noutputs++; + } + } else if (kev.flags & EV_ERROR) { + error = kev.data; + } + nchanges--; + } + + if ((flags & KEVENT_FLAG_ERROR_EVENTS) == 0 && + nevents > 0 && noutputs == 0 && error == 0) { + kectx->kec_process_flags = flags; + kectx->kec_process_nevents = nevents; + kectx->kec_process_noutputs = 0; + kectx->kec_process_eventlist = ueventlist; + + if (legacy) { + error = kqueue_scan(kqu.kq, flags, kectx, kevent_legacy_callback); + } else { + error = kqueue_scan(kqu.kq, flags, kectx, kevent_modern_callback); + } + + noutputs = kectx->kec_process_noutputs; + } else if (!legacy && (flags & KEVENT_FLAG_NEEDS_END_PROCESSING)) { + /* + * If we didn't through kqworkloop_end_processing(), + * we need to do it here. + * + * kqueue_scan will call kqworkloop_end_processing(), + * so we only need to do it if we didn't scan. + */ + kqlock(kqu); + kqworkloop_end_processing(kqu.kqwl, 0, 0); + kqunlock(kqu); + } + + *retval = noutputs; +out: + return kevent_cleanup(kqu.kq, flags, error, kectx); +} + +#pragma mark modern syscalls: kevent_qos, kevent_id, kevent_workq_internal + +/*! + * @function kevent_modern_internal + * + * @brief + * The backend of the kevent_id and kevent_workq_internal entry points. + * + * @discussion + * Needs to be inline due to the number of arguments. + */ +OS_NOINLINE +static int +kevent_modern_internal(kqueue_t kqu, + user_addr_t changelist, int nchanges, + user_addr_t ueventlist, int nevents, + int flags, kevent_ctx_t kectx, int32_t *retval) +{ + return kevent_internal(kqu.kq, changelist, nchanges, + ueventlist, nevents, flags, kectx, retval, /*legacy*/ false); +} + +/*! + * @function kevent_id + * + * @brief + * The kevent_id() syscall. + */ +int +kevent_id(struct proc *p, struct kevent_id_args *uap, int32_t *retval) +{ + int error, flags = uap->flags & KEVENT_FLAG_USER; + uthread_t uth = current_uthread(); + workq_threadreq_t kqr = uth->uu_kqr_bound; + kevent_ctx_t kectx = &uth->uu_save.uus_kevent; + kqueue_t kqu; + + flags = kevent_adjust_flags_for_proc(p, flags); + flags |= KEVENT_FLAG_DYNAMIC_KQUEUE; + + if (__improbable((flags & (KEVENT_FLAG_WORKQ | KEVENT_FLAG_WORKLOOP)) != + KEVENT_FLAG_WORKLOOP)) { + return EINVAL; + } + + error = kevent_get_data_size(flags, uap->data_available, uap->data_out, kectx); + if (__improbable(error)) { + return error; + } + + kectx->kec_deadline = 0; + kectx->kec_fp = NULL; + kectx->kec_fd = -1; + /* the kec_process_* fields are filled if kqueue_scann is called only */ + + /* + * Get the kq we are going to be working on + * As a fastpath, look at the currently bound workloop. + */ + kqu.kqwl = kqr ? kqr_kqworkloop(kqr) : NULL; + if (kqu.kqwl && kqu.kqwl->kqwl_dynamicid == uap->id) { + if (__improbable(flags & KEVENT_FLAG_DYNAMIC_KQ_MUST_NOT_EXIST)) { + return EEXIST; + } + kqworkloop_retain(kqu.kqwl); + } else if (__improbable(kevent_args_requesting_events(flags, uap->nevents))) { + return EXDEV; + } else { + error = kqworkloop_get_or_create(p, uap->id, NULL, flags, &kqu.kqwl); + if (__improbable(error)) { + return error; + } + } + + return kevent_modern_internal(kqu, uap->changelist, uap->nchanges, + uap->eventlist, uap->nevents, flags, kectx, retval); +} + +/**! + * @function kevent_workq_internal + * + * @discussion + * This function is exported for the sake of the workqueue subsystem. + * + * It is called in two ways: + * - when a thread is about to go to userspace to ask for pending event + * - when a thread is returning from userspace with events back + * + * the workqueue subsystem will only use the following flags: + * - KEVENT_FLAG_STACK_DATA (always) + * - KEVENT_FLAG_IMMEDIATE (always) + * - KEVENT_FLAG_PARKING (depending on whether it is going to or returning from + * userspace). + * + * It implicitly acts on the bound kqueue, and for the case of workloops + * will copyout the kqueue ID before anything else. + * + * + * Pthread will have setup the various arguments to fit this stack layout: + * + * +-------....----+--------------+-----------+--------------------+ + * | user stack | data avail | nevents | pthread_self() | + * +-------....----+--------------+-----------+--------------------+ + * ^ ^ + * data_out eventlist + * + * When a workloop is used, the workloop ID is copied out right before + * the eventlist and is taken from the data buffer. + * + * @warning + * This function is carefuly tailored to not make any call except the final tail + * call into kevent_modern_internal. (LTO inlines current_uthread()). + * + * This function is performance sensitive due to the workq subsystem. + */ +int +kevent_workq_internal(struct proc *p, + user_addr_t changelist, int nchanges, + user_addr_t eventlist, int nevents, + user_addr_t data_out, user_size_t *data_available, + unsigned int flags, int32_t *retval) +{ + uthread_t uth = current_uthread(); + workq_threadreq_t kqr = uth->uu_kqr_bound; + kevent_ctx_t kectx = &uth->uu_save.uus_kevent; + kqueue_t kqu; + + assert(flags == (KEVENT_FLAG_STACK_DATA | KEVENT_FLAG_IMMEDIATE) || + flags == (KEVENT_FLAG_STACK_DATA | KEVENT_FLAG_IMMEDIATE | KEVENT_FLAG_PARKING)); + + kectx->kec_data_out = data_out; + kectx->kec_data_avail = (uint64_t)data_available; + kectx->kec_data_size = *data_available; + kectx->kec_data_resid = *data_available; + kectx->kec_deadline = 0; + kectx->kec_fp = NULL; + kectx->kec_fd = -1; + /* the kec_process_* fields are filled if kqueue_scann is called only */ + + flags = kevent_adjust_flags_for_proc(p, flags); + + if (kqr->tr_flags & WORKQ_TR_FLAG_WORKLOOP) { + kqu.kqwl = __container_of(kqr, struct kqworkloop, kqwl_request); + kqworkloop_retain(kqu.kqwl); + + flags |= KEVENT_FLAG_WORKLOOP | KEVENT_FLAG_DYNAMIC_KQUEUE | + KEVENT_FLAG_KERNEL; + } else { + kqu.kqwq = p->p_fd->fd_wqkqueue; + + flags |= KEVENT_FLAG_WORKQ | KEVENT_FLAG_KERNEL; + } + + return kevent_modern_internal(kqu, changelist, nchanges, + eventlist, nevents, flags, kectx, retval); +} + +/*! + * @function kevent_qos + * + * @brief + * The kevent_qos() syscall. + */ +int +kevent_qos(struct proc *p, struct kevent_qos_args *uap, int32_t *retval) +{ + uthread_t uth = current_uthread(); + kevent_ctx_t kectx = &uth->uu_save.uus_kevent; + int error, flags = uap->flags & KEVENT_FLAG_USER; + struct kqueue *kq; + + if (__improbable(flags & KEVENT_ID_FLAG_USER)) { + return EINVAL; + } + + flags = kevent_adjust_flags_for_proc(p, flags); + + error = kevent_get_data_size(flags, uap->data_available, uap->data_out, kectx); + if (__improbable(error)) { + return error; + } + + kectx->kec_deadline = 0; + kectx->kec_fp = NULL; + kectx->kec_fd = uap->fd; + /* the kec_process_* fields are filled if kqueue_scann is called only */ + + /* get the kq we are going to be working on */ + if (__probable(flags & KEVENT_FLAG_WORKQ)) { + error = kevent_get_kqwq(p, flags, uap->nevents, &kq); + } else { + error = kevent_get_kqfile(p, uap->fd, flags, &kectx->kec_fp, &kq); + } + if (__improbable(error)) { + return error; + } + + return kevent_modern_internal(kq, uap->changelist, uap->nchanges, + uap->eventlist, uap->nevents, flags, kectx, retval); +} + +#pragma mark legacy syscalls: kevent, kevent64 + +/*! + * @function kevent_legacy_get_deadline + * + * @brief + * Compute the deadline for the legacy kevent syscalls. + * + * @discussion + * This is not necessary if KEVENT_FLAG_IMMEDIATE is specified, + * as this takes precedence over the deadline. + * + * This function will fail if utimeout is USER_ADDR_NULL + * (the caller should check). + */ +static int +kevent_legacy_get_deadline(int flags, user_addr_t utimeout, uint64_t *deadline) +{ + struct timespec ts; + + if (flags & KEVENT_FLAG_PROC64) { + struct user64_timespec ts64; + int error = copyin(utimeout, &ts64, sizeof(ts64)); + if (__improbable(error)) { + return error; + } + ts.tv_sec = ts64.tv_sec; + ts.tv_nsec = ts64.tv_nsec; + } else { + struct user32_timespec ts32; + int error = copyin(utimeout, &ts32, sizeof(ts32)); + if (__improbable(error)) { + return error; + } + ts.tv_sec = ts32.tv_sec; + ts.tv_nsec = ts32.tv_nsec; + } + if (!timespec_is_valid(&ts)) { + return EINVAL; + } + + clock_absolutetime_interval_to_deadline(tstoabstime(&ts), deadline); + return 0; +} + +/*! + * @function kevent_legacy_internal + * + * @brief + * The core implementation for kevent and kevent64 + */ +OS_NOINLINE +static int +kevent_legacy_internal(struct proc *p, struct kevent64_args *uap, + int32_t *retval, int flags) +{ + uthread_t uth = current_uthread(); + kevent_ctx_t kectx = &uth->uu_save.uus_kevent; + struct kqueue *kq; + int error; + + if (__improbable(uap->flags & KEVENT_ID_FLAG_USER)) { + return EINVAL; + } + + flags = kevent_adjust_flags_for_proc(p, flags); + + kectx->kec_data_out = 0; + kectx->kec_data_avail = 0; + kectx->kec_data_size = 0; + kectx->kec_data_resid = 0; + kectx->kec_deadline = 0; + kectx->kec_fp = NULL; + kectx->kec_fd = uap->fd; + /* the kec_process_* fields are filled if kqueue_scann is called only */ + + /* convert timeout to absolute - if we have one (and not immediate) */ + if (__improbable(uap->timeout && !(flags & KEVENT_FLAG_IMMEDIATE))) { + error = kevent_legacy_get_deadline(flags, uap->timeout, + &kectx->kec_deadline); + if (__improbable(error)) { + return error; + } + } + + /* get the kq we are going to be working on */ + if (flags & KEVENT_FLAG_WORKQ) { + error = kevent_get_kqwq(p, flags, uap->nevents, &kq); + } else { + error = kevent_get_kqfile(p, uap->fd, flags, &kectx->kec_fp, &kq); + } + if (__improbable(error)) { + return error; + } + + return kevent_internal(kq, uap->changelist, uap->nchanges, + uap->eventlist, uap->nevents, flags, kectx, retval, + /*legacy*/ true); +} + +/*! + * @function kevent + * + * @brief + * The legacy kevent() syscall. + */ +int +kevent(struct proc *p, struct kevent_args *uap, int32_t *retval) +{ + struct kevent64_args args = { + .fd = uap->fd, + .changelist = uap->changelist, + .nchanges = uap->nchanges, + .eventlist = uap->eventlist, + .nevents = uap->nevents, + .timeout = uap->timeout, + }; + + return kevent_legacy_internal(p, &args, retval, KEVENT_FLAG_LEGACY32); +} + +/*! + * @function kevent64 + * + * @brief + * The legacy kevent64() syscall. + */ +int +kevent64(struct proc *p, struct kevent64_args *uap, int32_t *retval) +{ + int flags = (uap->flags & KEVENT_FLAG_USER) | KEVENT_FLAG_LEGACY64; + return kevent_legacy_internal(p, uap, retval, flags); +} + +#pragma mark - socket interface + +#if SOCKETS +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#ifndef ROUNDUP64 +#define ROUNDUP64(x) P2ROUNDUP((x), sizeof (u_int64_t)) +#endif + +#ifndef ADVANCE64 +#define ADVANCE64(p, n) (void*)((char *)(p) + ROUNDUP64(n)) +#endif + +static lck_grp_attr_t *kev_lck_grp_attr; +static lck_attr_t *kev_lck_attr; +static lck_grp_t *kev_lck_grp; +static decl_lck_rw_data(, kev_lck_data); +static lck_rw_t *kev_rwlock = &kev_lck_data; + +static int kev_attach(struct socket *so, int proto, struct proc *p); +static int kev_detach(struct socket *so); +static int kev_control(struct socket *so, u_long cmd, caddr_t data, + struct ifnet *ifp, struct proc *p); +static lck_mtx_t * event_getlock(struct socket *, int); +static int event_lock(struct socket *, int, void *); +static int event_unlock(struct socket *, int, void *); + +static int event_sofreelastref(struct socket *); +static void kev_delete(struct kern_event_pcb *); + +static struct pr_usrreqs event_usrreqs = { + .pru_attach = kev_attach, + .pru_control = kev_control, + .pru_detach = kev_detach, + .pru_soreceive = soreceive, +}; + +static struct protosw eventsw[] = { + { + .pr_type = SOCK_RAW, + .pr_protocol = SYSPROTO_EVENT, + .pr_flags = PR_ATOMIC, + .pr_usrreqs = &event_usrreqs, + .pr_lock = event_lock, + .pr_unlock = event_unlock, + .pr_getlock = event_getlock, + } +}; + +__private_extern__ int kevt_getstat SYSCTL_HANDLER_ARGS; +__private_extern__ int kevt_pcblist SYSCTL_HANDLER_ARGS; + +SYSCTL_NODE(_net_systm, OID_AUTO, kevt, + CTLFLAG_RW | CTLFLAG_LOCKED, 0, "Kernel event family"); + +struct kevtstat kevtstat; +SYSCTL_PROC(_net_systm_kevt, OID_AUTO, stats, + CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED, 0, 0, + kevt_getstat, "S,kevtstat", ""); + +SYSCTL_PROC(_net_systm_kevt, OID_AUTO, pcblist, + CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED, 0, 0, + kevt_pcblist, "S,xkevtpcb", ""); + +static lck_mtx_t * +event_getlock(struct socket *so, int flags) +{ +#pragma unused(flags) + struct kern_event_pcb *ev_pcb = (struct kern_event_pcb *)so->so_pcb; + + if (so->so_pcb != NULL) { + if (so->so_usecount < 0) { + panic("%s: so=%p usecount=%d lrh= %s\n", __func__, + so, so->so_usecount, solockhistory_nr(so)); + } + /* NOTREACHED */ + } else { + panic("%s: so=%p NULL NO so_pcb %s\n", __func__, + so, solockhistory_nr(so)); + /* NOTREACHED */ + } + return &ev_pcb->evp_mtx; +} + +static int +event_lock(struct socket *so, int refcount, void *lr) +{ + void *lr_saved; + + if (lr == NULL) { + lr_saved = __builtin_return_address(0); + } else { + lr_saved = lr; + } + + if (so->so_pcb != NULL) { + lck_mtx_lock(&((struct kern_event_pcb *)so->so_pcb)->evp_mtx); + } else { + panic("%s: so=%p NO PCB! lr=%p lrh= %s\n", __func__, + so, lr_saved, solockhistory_nr(so)); + /* NOTREACHED */ + } + + if (so->so_usecount < 0) { + panic("%s: so=%p so_pcb=%p lr=%p ref=%d lrh= %s\n", __func__, + so, so->so_pcb, lr_saved, so->so_usecount, + solockhistory_nr(so)); + /* NOTREACHED */ + } + + if (refcount) { + so->so_usecount++; + } + + so->lock_lr[so->next_lock_lr] = lr_saved; + so->next_lock_lr = (so->next_lock_lr + 1) % SO_LCKDBG_MAX; + return 0; +} + +static int +event_unlock(struct socket *so, int refcount, void *lr) +{ + void *lr_saved; + lck_mtx_t *mutex_held; + + if (lr == NULL) { + lr_saved = __builtin_return_address(0); + } else { + lr_saved = lr; + } + + if (refcount) { + so->so_usecount--; + } + if (so->so_usecount < 0) { + panic("%s: so=%p usecount=%d lrh= %s\n", __func__, + so, so->so_usecount, solockhistory_nr(so)); + /* NOTREACHED */ + } + if (so->so_pcb == NULL) { + panic("%s: so=%p NO PCB usecount=%d lr=%p lrh= %s\n", __func__, + so, so->so_usecount, (void *)lr_saved, + solockhistory_nr(so)); + /* NOTREACHED */ + } + mutex_held = (&((struct kern_event_pcb *)so->so_pcb)->evp_mtx); + + LCK_MTX_ASSERT(mutex_held, LCK_MTX_ASSERT_OWNED); + so->unlock_lr[so->next_unlock_lr] = lr_saved; + so->next_unlock_lr = (so->next_unlock_lr + 1) % SO_LCKDBG_MAX; + + if (so->so_usecount == 0) { + VERIFY(so->so_flags & SOF_PCBCLEARING); + event_sofreelastref(so); + } else { + lck_mtx_unlock(mutex_held); + } + + return 0; +} + +static int +event_sofreelastref(struct socket *so) +{ + struct kern_event_pcb *ev_pcb = (struct kern_event_pcb *)so->so_pcb; + + LCK_MTX_ASSERT(&(ev_pcb->evp_mtx), LCK_MTX_ASSERT_OWNED); + + so->so_pcb = NULL; + + /* + * Disable upcall in the event another thread is in kev_post_msg() + * appending record to the receive socket buffer, since sbwakeup() + * may release the socket lock otherwise. + */ + so->so_rcv.sb_flags &= ~SB_UPCALL; + so->so_snd.sb_flags &= ~SB_UPCALL; + so->so_event = sonullevent; + lck_mtx_unlock(&(ev_pcb->evp_mtx)); + + LCK_MTX_ASSERT(&(ev_pcb->evp_mtx), LCK_MTX_ASSERT_NOTOWNED); + lck_rw_lock_exclusive(kev_rwlock); + LIST_REMOVE(ev_pcb, evp_link); + kevtstat.kes_pcbcount--; + kevtstat.kes_gencnt++; + lck_rw_done(kev_rwlock); + kev_delete(ev_pcb); + + sofreelastref(so, 1); + return 0; +} + +static int event_proto_count = (sizeof(eventsw) / sizeof(struct protosw)); + +static +struct kern_event_head kern_event_head; + +static u_int32_t static_event_id = 0; + +#define EVPCB_ZONE_MAX 65536 +#define EVPCB_ZONE_NAME "kerneventpcb" +static struct zone *ev_pcb_zone; + +/* + * Install the protosw's for the NKE manager. Invoked at extension load time + */ +void +kern_event_init(struct domain *dp) +{ + struct protosw *pr; + int i; + + VERIFY(!(dp->dom_flags & DOM_INITIALIZED)); + VERIFY(dp == systemdomain); + + kev_lck_grp_attr = lck_grp_attr_alloc_init(); + if (kev_lck_grp_attr == NULL) { + panic("%s: lck_grp_attr_alloc_init failed\n", __func__); + /* NOTREACHED */ + } + + kev_lck_grp = lck_grp_alloc_init("Kernel Event Protocol", + kev_lck_grp_attr); + if (kev_lck_grp == NULL) { + panic("%s: lck_grp_alloc_init failed\n", __func__); + /* NOTREACHED */ + } + + kev_lck_attr = lck_attr_alloc_init(); + if (kev_lck_attr == NULL) { + panic("%s: lck_attr_alloc_init failed\n", __func__); + /* NOTREACHED */ + } + + lck_rw_init(kev_rwlock, kev_lck_grp, kev_lck_attr); + if (kev_rwlock == NULL) { + panic("%s: lck_mtx_alloc_init failed\n", __func__); + /* NOTREACHED */ + } + + for (i = 0, pr = &eventsw[0]; i < event_proto_count; i++, pr++) { + net_add_proto(pr, dp, 1); + } + + ev_pcb_zone = zinit(sizeof(struct kern_event_pcb), + EVPCB_ZONE_MAX * sizeof(struct kern_event_pcb), 0, EVPCB_ZONE_NAME); + if (ev_pcb_zone == NULL) { + panic("%s: failed allocating ev_pcb_zone", __func__); + /* NOTREACHED */ + } + zone_change(ev_pcb_zone, Z_EXPAND, TRUE); + zone_change(ev_pcb_zone, Z_CALLERACCT, TRUE); +} + +static int +kev_attach(struct socket *so, __unused int proto, __unused struct proc *p) +{ + int error = 0; + struct kern_event_pcb *ev_pcb; + + error = soreserve(so, KEV_SNDSPACE, KEV_RECVSPACE); + if (error != 0) { + return error; + } + + if ((ev_pcb = (struct kern_event_pcb *)zalloc(ev_pcb_zone)) == NULL) { + return ENOBUFS; + } + bzero(ev_pcb, sizeof(struct kern_event_pcb)); + lck_mtx_init(&ev_pcb->evp_mtx, kev_lck_grp, kev_lck_attr); + + ev_pcb->evp_socket = so; + ev_pcb->evp_vendor_code_filter = 0xffffffff; + + so->so_pcb = (caddr_t) ev_pcb; + lck_rw_lock_exclusive(kev_rwlock); + LIST_INSERT_HEAD(&kern_event_head, ev_pcb, evp_link); + kevtstat.kes_pcbcount++; + kevtstat.kes_gencnt++; + lck_rw_done(kev_rwlock); + + return error; +} + +static void +kev_delete(struct kern_event_pcb *ev_pcb) +{ + VERIFY(ev_pcb != NULL); + lck_mtx_destroy(&ev_pcb->evp_mtx, kev_lck_grp); + zfree(ev_pcb_zone, ev_pcb); +} + +static int +kev_detach(struct socket *so) +{ + struct kern_event_pcb *ev_pcb = (struct kern_event_pcb *) so->so_pcb; + + if (ev_pcb != NULL) { + soisdisconnected(so); + so->so_flags |= SOF_PCBCLEARING; + } + + return 0; +} + +/* + * For now, kev_vendor_code and mbuf_tags use the same + * mechanism. + */ +errno_t +kev_vendor_code_find( + const char *string, + u_int32_t *out_vendor_code) +{ + if (strlen(string) >= KEV_VENDOR_CODE_MAX_STR_LEN) { + return EINVAL; + } + return net_str_id_find_internal(string, out_vendor_code, + NSI_VENDOR_CODE, 1); +} + +errno_t +kev_msg_post(struct kev_msg *event_msg) +{ + mbuf_tag_id_t min_vendor, max_vendor; + + net_str_id_first_last(&min_vendor, &max_vendor, NSI_VENDOR_CODE); + + if (event_msg == NULL) { + return EINVAL; + } + + /* + * Limit third parties to posting events for registered vendor codes + * only + */ + if (event_msg->vendor_code < min_vendor || + event_msg->vendor_code > max_vendor) { + os_atomic_inc(&kevtstat.kes_badvendor, relaxed); + return EINVAL; + } + return kev_post_msg(event_msg); +} + +int +kev_post_msg(struct kev_msg *event_msg) +{ + struct mbuf *m, *m2; + struct kern_event_pcb *ev_pcb; + struct kern_event_msg *ev; + char *tmp; + u_int32_t total_size; + int i; + + /* Verify the message is small enough to fit in one mbuf w/o cluster */ + total_size = KEV_MSG_HEADER_SIZE; + + for (i = 0; i < 5; i++) { + if (event_msg->dv[i].data_length == 0) { + break; + } + total_size += event_msg->dv[i].data_length; + } + + if (total_size > MLEN) { + os_atomic_inc(&kevtstat.kes_toobig, relaxed); + return EMSGSIZE; + } + + m = m_get(M_WAIT, MT_DATA); + if (m == 0) { + os_atomic_inc(&kevtstat.kes_nomem, relaxed); + return ENOMEM; + } + ev = mtod(m, struct kern_event_msg *); + total_size = KEV_MSG_HEADER_SIZE; + + tmp = (char *) &ev->event_data[0]; + for (i = 0; i < 5; i++) { + if (event_msg->dv[i].data_length == 0) { + break; + } + + total_size += event_msg->dv[i].data_length; + bcopy(event_msg->dv[i].data_ptr, tmp, + event_msg->dv[i].data_length); + tmp += event_msg->dv[i].data_length; + } + + ev->id = ++static_event_id; + ev->total_size = total_size; + ev->vendor_code = event_msg->vendor_code; + ev->kev_class = event_msg->kev_class; + ev->kev_subclass = event_msg->kev_subclass; + ev->event_code = event_msg->event_code; + + m->m_len = total_size; + lck_rw_lock_shared(kev_rwlock); + for (ev_pcb = LIST_FIRST(&kern_event_head); + ev_pcb; + ev_pcb = LIST_NEXT(ev_pcb, evp_link)) { + lck_mtx_lock(&ev_pcb->evp_mtx); + if (ev_pcb->evp_socket->so_pcb == NULL) { + lck_mtx_unlock(&ev_pcb->evp_mtx); + continue; + } + if (ev_pcb->evp_vendor_code_filter != KEV_ANY_VENDOR) { + if (ev_pcb->evp_vendor_code_filter != ev->vendor_code) { + lck_mtx_unlock(&ev_pcb->evp_mtx); + continue; + } + + if (ev_pcb->evp_class_filter != KEV_ANY_CLASS) { + if (ev_pcb->evp_class_filter != ev->kev_class) { + lck_mtx_unlock(&ev_pcb->evp_mtx); + continue; + } + + if ((ev_pcb->evp_subclass_filter != + KEV_ANY_SUBCLASS) && + (ev_pcb->evp_subclass_filter != + ev->kev_subclass)) { + lck_mtx_unlock(&ev_pcb->evp_mtx); + continue; + } + } + } + + m2 = m_copym(m, 0, m->m_len, M_WAIT); + if (m2 == 0) { + os_atomic_inc(&kevtstat.kes_nomem, relaxed); + m_free(m); + lck_mtx_unlock(&ev_pcb->evp_mtx); + lck_rw_done(kev_rwlock); + return ENOMEM; + } + if (sbappendrecord(&ev_pcb->evp_socket->so_rcv, m2)) { + /* + * We use "m" for the socket stats as it would be + * unsafe to use "m2" + */ + so_inc_recv_data_stat(ev_pcb->evp_socket, + 1, m->m_len, MBUF_TC_BE); + + sorwakeup(ev_pcb->evp_socket); + os_atomic_inc(&kevtstat.kes_posted, relaxed); + } else { + os_atomic_inc(&kevtstat.kes_fullsock, relaxed); + } + lck_mtx_unlock(&ev_pcb->evp_mtx); + } + m_free(m); + lck_rw_done(kev_rwlock); + + return 0; +} + +static int +kev_control(struct socket *so, + u_long cmd, + caddr_t data, + __unused struct ifnet *ifp, + __unused struct proc *p) +{ + struct kev_request *kev_req = (struct kev_request *) data; + struct kern_event_pcb *ev_pcb; + struct kev_vendor_code *kev_vendor; + u_int32_t *id_value = (u_int32_t *) data; + + switch (cmd) { + case SIOCGKEVID: + *id_value = static_event_id; + break; + case SIOCSKEVFILT: + ev_pcb = (struct kern_event_pcb *) so->so_pcb; + ev_pcb->evp_vendor_code_filter = kev_req->vendor_code; + ev_pcb->evp_class_filter = kev_req->kev_class; + ev_pcb->evp_subclass_filter = kev_req->kev_subclass; + break; + case SIOCGKEVFILT: + ev_pcb = (struct kern_event_pcb *) so->so_pcb; + kev_req->vendor_code = ev_pcb->evp_vendor_code_filter; + kev_req->kev_class = ev_pcb->evp_class_filter; + kev_req->kev_subclass = ev_pcb->evp_subclass_filter; + break; + case SIOCGKEVVENDOR: + kev_vendor = (struct kev_vendor_code *)data; + /* Make sure string is NULL terminated */ + kev_vendor->vendor_string[KEV_VENDOR_CODE_MAX_STR_LEN - 1] = 0; + return net_str_id_find_internal(kev_vendor->vendor_string, + &kev_vendor->vendor_code, NSI_VENDOR_CODE, 0); + default: + return ENOTSUP; + } + + return 0; +} + +int +kevt_getstat SYSCTL_HANDLER_ARGS +{ +#pragma unused(oidp, arg1, arg2) + int error = 0; + + lck_rw_lock_shared(kev_rwlock); + + if (req->newptr != USER_ADDR_NULL) { + error = EPERM; + goto done; + } + if (req->oldptr == USER_ADDR_NULL) { + req->oldidx = sizeof(struct kevtstat); + goto done; + } + + error = SYSCTL_OUT(req, &kevtstat, + MIN(sizeof(struct kevtstat), req->oldlen)); +done: + lck_rw_done(kev_rwlock); + + return error; +} + +__private_extern__ int +kevt_pcblist SYSCTL_HANDLER_ARGS +{ +#pragma unused(oidp, arg1, arg2) + int error = 0; + int n, i; + struct xsystmgen xsg; + void *buf = NULL; + size_t item_size = ROUNDUP64(sizeof(struct xkevtpcb)) + + ROUNDUP64(sizeof(struct xsocket_n)) + + 2 * ROUNDUP64(sizeof(struct xsockbuf_n)) + + ROUNDUP64(sizeof(struct xsockstat_n)); + struct kern_event_pcb *ev_pcb; + + buf = _MALLOC(item_size, M_TEMP, M_WAITOK | M_ZERO); + if (buf == NULL) { + return ENOMEM; + } + + lck_rw_lock_shared(kev_rwlock); + + n = kevtstat.kes_pcbcount; + + if (req->oldptr == USER_ADDR_NULL) { + req->oldidx = (n + n / 8) * item_size; + goto done; + } + if (req->newptr != USER_ADDR_NULL) { + error = EPERM; + goto done; + } + bzero(&xsg, sizeof(xsg)); + xsg.xg_len = sizeof(xsg); + xsg.xg_count = n; + xsg.xg_gen = kevtstat.kes_gencnt; + xsg.xg_sogen = so_gencnt; + error = SYSCTL_OUT(req, &xsg, sizeof(xsg)); + if (error) { + goto done; + } + /* + * We are done if there is no pcb + */ + if (n == 0) { + goto done; + } + + i = 0; + for (i = 0, ev_pcb = LIST_FIRST(&kern_event_head); + i < n && ev_pcb != NULL; + i++, ev_pcb = LIST_NEXT(ev_pcb, evp_link)) { + struct xkevtpcb *xk = (struct xkevtpcb *)buf; + struct xsocket_n *xso = (struct xsocket_n *) + ADVANCE64(xk, sizeof(*xk)); + struct xsockbuf_n *xsbrcv = (struct xsockbuf_n *) + ADVANCE64(xso, sizeof(*xso)); + struct xsockbuf_n *xsbsnd = (struct xsockbuf_n *) + ADVANCE64(xsbrcv, sizeof(*xsbrcv)); + struct xsockstat_n *xsostats = (struct xsockstat_n *) + ADVANCE64(xsbsnd, sizeof(*xsbsnd)); + + bzero(buf, item_size); + + lck_mtx_lock(&ev_pcb->evp_mtx); + + xk->kep_len = sizeof(struct xkevtpcb); + xk->kep_kind = XSO_EVT; + xk->kep_evtpcb = (uint64_t)VM_KERNEL_ADDRPERM(ev_pcb); + xk->kep_vendor_code_filter = ev_pcb->evp_vendor_code_filter; + xk->kep_class_filter = ev_pcb->evp_class_filter; + xk->kep_subclass_filter = ev_pcb->evp_subclass_filter; + + sotoxsocket_n(ev_pcb->evp_socket, xso); + sbtoxsockbuf_n(ev_pcb->evp_socket ? + &ev_pcb->evp_socket->so_rcv : NULL, xsbrcv); + sbtoxsockbuf_n(ev_pcb->evp_socket ? + &ev_pcb->evp_socket->so_snd : NULL, xsbsnd); + sbtoxsockstat_n(ev_pcb->evp_socket, xsostats); + + lck_mtx_unlock(&ev_pcb->evp_mtx); + + error = SYSCTL_OUT(req, buf, item_size); + } + + if (error == 0) { + /* + * Give the user an updated idea of our state. + * If the generation differs from what we told + * her before, she knows that something happened + * while we were processing this request, and it + * might be necessary to retry. + */ + bzero(&xsg, sizeof(xsg)); + xsg.xg_len = sizeof(xsg); + xsg.xg_count = n; + xsg.xg_gen = kevtstat.kes_gencnt; + xsg.xg_sogen = so_gencnt; + error = SYSCTL_OUT(req, &xsg, sizeof(xsg)); + if (error) { + goto done; + } + } + +done: + lck_rw_done(kev_rwlock); + + return error; +} + +#endif /* SOCKETS */ + + +int +fill_kqueueinfo(struct kqueue *kq, struct kqueue_info * kinfo) +{ + struct vinfo_stat * st; + + st = &kinfo->kq_stat; + + st->vst_size = kq->kq_count; + if (kq->kq_state & KQ_KEV_QOS) { + st->vst_blksize = sizeof(struct kevent_qos_s); + } else if (kq->kq_state & KQ_KEV64) { + st->vst_blksize = sizeof(struct kevent64_s); + } else { + st->vst_blksize = sizeof(struct kevent); + } + st->vst_mode = S_IFIFO; + st->vst_ino = (kq->kq_state & KQ_DYNAMIC) ? + ((struct kqworkloop *)kq)->kqwl_dynamicid : 0; + + /* flags exported to libproc as PROC_KQUEUE_* (sys/proc_info.h) */ +#define PROC_KQUEUE_MASK (KQ_SEL|KQ_SLEEP|KQ_KEV32|KQ_KEV64|KQ_KEV_QOS|KQ_WORKQ|KQ_WORKLOOP) + kinfo->kq_state = kq->kq_state & PROC_KQUEUE_MASK; + + return 0; +} + +static int +fill_kqueue_dyninfo(struct kqworkloop *kqwl, struct kqueue_dyninfo *kqdi) +{ + workq_threadreq_t kqr = &kqwl->kqwl_request; + workq_threadreq_param_t trp = {}; + int err; + + if ((kqwl->kqwl_state & KQ_WORKLOOP) == 0) { + return EINVAL; + } + + if ((err = fill_kqueueinfo(&kqwl->kqwl_kqueue, &kqdi->kqdi_info))) { + return err; + } + + kqlock(kqwl); + + kqdi->kqdi_servicer = thread_tid(kqr_thread(kqr)); + kqdi->kqdi_owner = thread_tid(kqwl->kqwl_owner); + kqdi->kqdi_request_state = kqr->tr_state; + kqdi->kqdi_async_qos = kqr->tr_kq_qos_index; + kqdi->kqdi_events_qos = kqr->tr_kq_override_index; + kqdi->kqdi_sync_waiters = 0; + kqdi->kqdi_sync_waiter_qos = 0; + + trp.trp_value = kqwl->kqwl_params; + if (trp.trp_flags & TRP_PRIORITY) { + kqdi->kqdi_pri = trp.trp_pri; + } else { + kqdi->kqdi_pri = 0; + } + + if (trp.trp_flags & TRP_POLICY) { + kqdi->kqdi_pol = trp.trp_pol; + } else { + kqdi->kqdi_pol = 0; + } + + if (trp.trp_flags & TRP_CPUPERCENT) { + kqdi->kqdi_cpupercent = trp.trp_cpupercent; + } else { + kqdi->kqdi_cpupercent = 0; + } + + kqunlock(kqwl); + + return 0; +} + + +void +knote_markstayactive(struct knote *kn) +{ + struct kqueue *kq = knote_get_kq(kn); + kq_index_t qos; + + kqlock(kq); + kn->kn_status |= KN_STAYACTIVE; + + /* + * Making a knote stay active is a property of the knote that must be + * established before it is fully attached. + */ + assert((kn->kn_status & (KN_QUEUED | KN_SUPPRESSED)) == 0); + + /* handle all stayactive knotes on the (appropriate) manager */ + if (kq->kq_state & KQ_WORKLOOP) { + struct kqworkloop *kqwl = (struct kqworkloop *)kq; + + qos = _pthread_priority_thread_qos(kn->kn_qos); + assert(qos && qos < THREAD_QOS_LAST); + kqworkloop_update_threads_qos(kqwl, KQWL_UTQ_UPDATE_STAYACTIVE_QOS, qos); + qos = KQWL_BUCKET_STAYACTIVE; + } else if (kq->kq_state & KQ_WORKQ) { + qos = KQWQ_QOS_MANAGER; + } else { + qos = THREAD_QOS_UNSPECIFIED; + } + + kn->kn_qos_override = qos; + kn->kn_qos_index = qos; + + knote_activate(kq, kn, FILTER_ACTIVE); + kqunlock(kq); +} + +void +knote_clearstayactive(struct knote *kn) +{ + struct kqueue *kq = knote_get_kq(kn); + kqlock(kq); + kn->kn_status &= ~(KN_STAYACTIVE | KN_ACTIVE); + knote_dequeue(kq, kn); + kqunlock(kq); +} + +static unsigned long +kevent_extinfo_emit(struct kqueue *kq, struct knote *kn, struct kevent_extinfo *buf, + unsigned long buflen, unsigned long nknotes) +{ + for (; kn; kn = SLIST_NEXT(kn, kn_link)) { + if (kq == knote_get_kq(kn)) { + if (nknotes < buflen) { + struct kevent_extinfo *info = &buf[nknotes]; + + kqlock(kq); + + info->kqext_kev = *(struct kevent_qos_s *)&kn->kn_kevent; + if (knote_has_qos(kn)) { + info->kqext_kev.qos = + _pthread_priority_thread_qos_fast(kn->kn_qos); + } else { + info->kqext_kev.qos = kn->kn_qos_override; + } + info->kqext_kev.filter |= 0xff00; /* sign extend filter */ + info->kqext_kev.xflags = 0; /* this is where sfflags lives */ + info->kqext_kev.data = 0; /* this is where sdata lives */ + info->kqext_sdata = kn->kn_sdata; + info->kqext_status = kn->kn_status; + info->kqext_sfflags = kn->kn_sfflags; + + kqunlock(kq); + } + + /* we return total number of knotes, which may be more than requested */ + nknotes++; + } + } + + return nknotes; +} + +int +kevent_copyout_proc_dynkqids(void *proc, user_addr_t ubuf, uint32_t ubufsize, + int32_t *nkqueues_out) +{ + proc_t p = (proc_t)proc; + struct filedesc *fdp = p->p_fd; + unsigned int nkqueues = 0; + unsigned long ubuflen = ubufsize / sizeof(kqueue_id_t); + size_t buflen, bufsize; + kqueue_id_t *kq_ids = NULL; + int err = 0; + + assert(p != NULL); + + if (ubuf == USER_ADDR_NULL && ubufsize != 0) { + err = EINVAL; + goto out; + } + + buflen = min(ubuflen, PROC_PIDDYNKQUEUES_MAX); + + if (ubuflen != 0) { + if (os_mul_overflow(sizeof(kqueue_id_t), buflen, &bufsize)) { + err = ERANGE; + goto out; + } + kq_ids = kalloc(bufsize); + if (!kq_ids) { + err = ENOMEM; + goto out; + } + bzero(kq_ids, bufsize); + } + + kqhash_lock(fdp); + + if (fdp->fd_kqhashmask > 0) { + for (uint32_t i = 0; i < fdp->fd_kqhashmask + 1; i++) { + struct kqworkloop *kqwl; + + LIST_FOREACH(kqwl, &fdp->fd_kqhash[i], kqwl_hashlink) { + /* report the number of kqueues, even if they don't all fit */ + if (nkqueues < buflen) { + kq_ids[nkqueues] = kqwl->kqwl_dynamicid; + } + nkqueues++; + } + } + } + + kqhash_unlock(fdp); + + if (kq_ids) { + size_t copysize; + if (os_mul_overflow(sizeof(kqueue_id_t), min(buflen, nkqueues), ©size)) { + err = ERANGE; + goto out; + } + + assert(ubufsize >= copysize); + err = copyout(kq_ids, ubuf, copysize); + } + +out: + if (kq_ids) { + kfree(kq_ids, bufsize); + } + + if (!err) { + *nkqueues_out = (int)min(nkqueues, PROC_PIDDYNKQUEUES_MAX); + } + return err; +} + +int +kevent_copyout_dynkqinfo(void *proc, kqueue_id_t kq_id, user_addr_t ubuf, + uint32_t ubufsize, int32_t *size_out) +{ + proc_t p = (proc_t)proc; + struct kqworkloop *kqwl; + int err = 0; + struct kqueue_dyninfo kqdi = { }; + + assert(p != NULL); + + if (ubufsize < sizeof(struct kqueue_info)) { + return ENOBUFS; + } + + kqwl = kqworkloop_hash_lookup_and_retain(p->p_fd, kq_id); + if (!kqwl) { + return ESRCH; + } + + /* + * backward compatibility: allow the argument to this call to only be + * a struct kqueue_info + */ + if (ubufsize >= sizeof(struct kqueue_dyninfo)) { + ubufsize = sizeof(struct kqueue_dyninfo); + err = fill_kqueue_dyninfo(kqwl, &kqdi); + } else { + ubufsize = sizeof(struct kqueue_info); + err = fill_kqueueinfo(&kqwl->kqwl_kqueue, &kqdi.kqdi_info); + } + if (err == 0 && (err = copyout(&kqdi, ubuf, ubufsize)) == 0) { + *size_out = ubufsize; + } + kqworkloop_release(kqwl); + return err; +} + +int +kevent_copyout_dynkqextinfo(void *proc, kqueue_id_t kq_id, user_addr_t ubuf, + uint32_t ubufsize, int32_t *nknotes_out) +{ + proc_t p = (proc_t)proc; + struct kqworkloop *kqwl; + int err; + + kqwl = kqworkloop_hash_lookup_and_retain(p->p_fd, kq_id); + if (!kqwl) { + return ESRCH; + } + + err = pid_kqueue_extinfo(p, &kqwl->kqwl_kqueue, ubuf, ubufsize, nknotes_out); + kqworkloop_release(kqwl); + return err; +} + +int +pid_kqueue_extinfo(proc_t p, struct kqueue *kq, user_addr_t ubuf, + uint32_t bufsize, int32_t *retval) +{ + struct knote *kn; + int i; + int err = 0; + struct filedesc *fdp = p->p_fd; + unsigned long nknotes = 0; + unsigned long buflen = bufsize / sizeof(struct kevent_extinfo); + struct kevent_extinfo *kqext = NULL; + + /* arbitrary upper limit to cap kernel memory usage, copyout size, etc. */ + buflen = min(buflen, PROC_PIDFDKQUEUE_KNOTES_MAX); + + kqext = kalloc(buflen * sizeof(struct kevent_extinfo)); + if (kqext == NULL) { + err = ENOMEM; + goto out; + } + bzero(kqext, buflen * sizeof(struct kevent_extinfo)); + + proc_fdlock(p); + for (i = 0; i < fdp->fd_knlistsize; i++) { + kn = SLIST_FIRST(&fdp->fd_knlist[i]); + nknotes = kevent_extinfo_emit(kq, kn, kqext, buflen, nknotes); + } + proc_fdunlock(p); + + if (fdp->fd_knhashmask != 0) { + for (i = 0; i < (int)fdp->fd_knhashmask + 1; i++) { + knhash_lock(fdp); + kn = SLIST_FIRST(&fdp->fd_knhash[i]); + nknotes = kevent_extinfo_emit(kq, kn, kqext, buflen, nknotes); + knhash_unlock(fdp); + } + } + + assert(bufsize >= sizeof(struct kevent_extinfo) * min(buflen, nknotes)); + err = copyout(kqext, ubuf, sizeof(struct kevent_extinfo) * min(buflen, nknotes)); + +out: + if (kqext) { + kfree(kqext, buflen * sizeof(struct kevent_extinfo)); + kqext = NULL; + } + + if (!err) { + *retval = min(nknotes, PROC_PIDFDKQUEUE_KNOTES_MAX); + } + return err; +} + +static unsigned int +klist_copy_udata(struct klist *list, uint64_t *buf, + unsigned int buflen, unsigned int nknotes) +{ + struct knote *kn; + SLIST_FOREACH(kn, list, kn_link) { + if (nknotes < buflen) { + /* + * kevent_register will always set kn_udata atomically + * so that we don't have to take any kqlock here. + */ + buf[nknotes] = os_atomic_load_wide(&kn->kn_udata, relaxed); + } + /* we return total number of knotes, which may be more than requested */ + nknotes++; + } + + return nknotes; +} + +int +kevent_proc_copy_uptrs(void *proc, uint64_t *buf, int bufsize) +{ + proc_t p = (proc_t)proc; + struct filedesc *fdp = p->p_fd; + unsigned int nuptrs = 0; + unsigned long buflen = bufsize / sizeof(uint64_t); + struct kqworkloop *kqwl; + + if (buflen > 0) { + assert(buf != NULL); + } + + proc_fdlock(p); + for (int i = 0; i < fdp->fd_knlistsize; i++) { + nuptrs = klist_copy_udata(&fdp->fd_knlist[i], buf, buflen, nuptrs); + } + proc_fdunlock(p); + + knhash_lock(fdp); + if (fdp->fd_knhashmask != 0) { + for (size_t i = 0; i < fdp->fd_knhashmask + 1; i++) { + nuptrs = klist_copy_udata(&fdp->fd_knhash[i], buf, buflen, nuptrs); + } + } + knhash_unlock(fdp); + + kqhash_lock(fdp); + if (fdp->fd_kqhashmask != 0) { + for (size_t i = 0; i < fdp->fd_kqhashmask + 1; i++) { + LIST_FOREACH(kqwl, &fdp->fd_kqhash[i], kqwl_hashlink) { + if (nuptrs < buflen) { + buf[nuptrs] = kqwl->kqwl_dynamicid; + } + nuptrs++; + } + } + } + kqhash_unlock(fdp); + + return (int)nuptrs; +} + +static void +kevent_set_return_to_kernel_user_tsd(proc_t p, thread_t thread) +{ + uint64_t ast_addr; + bool proc_is_64bit = !!(p->p_flag & P_LP64); + size_t user_addr_size = proc_is_64bit ? 8 : 4; + uint32_t ast_flags32 = 0; + uint64_t ast_flags64 = 0; + struct uthread *ut = get_bsdthread_info(thread); + + if (ut->uu_kqr_bound != NULL) { + ast_flags64 |= R2K_WORKLOOP_PENDING_EVENTS; + } + + if (ast_flags64 == 0) { + return; + } + + if (!(p->p_flag & P_LP64)) { + ast_flags32 = (uint32_t)ast_flags64; + assert(ast_flags64 < 0x100000000ull); + } + + ast_addr = thread_rettokern_addr(thread); + if (ast_addr == 0) { + return; + } + + if (copyout((proc_is_64bit ? (void *)&ast_flags64 : (void *)&ast_flags32), + (user_addr_t)ast_addr, + user_addr_size) != 0) { + printf("pid %d (tid:%llu): copyout of return_to_kernel ast flags failed with " + "ast_addr = %llu\n", p->p_pid, thread_tid(current_thread()), ast_addr); + } +} + +void +kevent_ast(thread_t thread, uint16_t bits) +{ + proc_t p = current_proc(); + + if (bits & AST_KEVENT_REDRIVE_THREADREQ) { + workq_kern_threadreq_redrive(p, WORKQ_THREADREQ_CAN_CREATE_THREADS); + } + if (bits & AST_KEVENT_RETURN_TO_KERNEL) { + kevent_set_return_to_kernel_user_tsd(p, thread); + } +} + +#if DEVELOPMENT || DEBUG + +#define KEVENT_SYSCTL_BOUND_ID 1 + +static int +kevent_sysctl SYSCTL_HANDLER_ARGS +{ +#pragma unused(oidp, arg2) + uintptr_t type = (uintptr_t)arg1; + uint64_t bound_id = 0; + + if (type != KEVENT_SYSCTL_BOUND_ID) { + return EINVAL; + } + + if (req->newptr) { + return EINVAL; + } + + struct uthread *ut = get_bsdthread_info(current_thread()); + if (!ut) { + return EFAULT; + } + + workq_threadreq_t kqr = ut->uu_kqr_bound; + if (kqr) { + if (kqr->tr_flags & WORKQ_TR_FLAG_WORKLOOP) { + bound_id = kqr_kqworkloop(kqr)->kqwl_dynamicid; + } else { + bound_id = -1; + } + } + + return sysctl_io_number(req, bound_id, sizeof(bound_id), NULL, NULL); +} + +SYSCTL_NODE(_kern, OID_AUTO, kevent, CTLFLAG_RW | CTLFLAG_LOCKED, 0, + "kevent information"); +SYSCTL_PROC(_kern_kevent, OID_AUTO, bound_id, + CTLTYPE_QUAD | CTLFLAG_RD | CTLFLAG_LOCKED | CTLFLAG_MASKED, + (void *)KEVENT_SYSCTL_BOUND_ID, + sizeof(kqueue_id_t), kevent_sysctl, "Q", + "get the ID of the bound kqueue"); +#endif /* DEVELOPMENT || DEBUG */